diff --git a/docs/economy/otivm_iv_cost_calibration_additional_goods.md b/docs/economy/otivm_iv_cost_calibration_additional_goods.md new file mode 100644 index 0000000..18029cf --- /dev/null +++ b/docs/economy/otivm_iv_cost_calibration_additional_goods.md @@ -0,0 +1,486 @@ +# OTIVM-IV Cost Calibration Model — Additional Goods, c. 14 BCE + +**Prepared for:** OTIVM-IV / CIVICVS Simulator +**Date:** 2026-05-03 +**Status:** Calibrated historical-economic model, not a claim of exact reconstruction +**Previous document:** `otivm_iv_cost_calibration_model.md` (ceramic cup baseline) +**Currency:** 1 dn = 16 as (unchanged) + +--- + +## Compatibility constants inherited from the ceramic baseline + +```text +AS_PER_DENARIUS = 16 +WAGE_UNSKILLED_DAY_DN = 0.50 +WAGE_SKILLED_ARTISAN_DN = 1.00 +WAGE_MERCHANT_SELF_DN = 1.00 +WHEAT_MODIUS_DN = 0.75 +PORTORIA_AD_VALOREM_RATE = 0.025 +CERAMIC_CUP_PLAIN_LOCAL_AS = 2.00 +CERAMIC_CUP_FINE_LOCAL_AS = 4.00 +``` + +Values below preserve the same method as the first document: source-backed anchors where possible, analogical conversions where evidence is adjacent, and explicit simulator calibration where the equation needs a value but the surviving evidence is not price-complete. + +--- + +## Good 1 — Garum + +Garum is economically distinctive because it is coastal, specialist, salt-intensive, batch-produced, and quality-stratified: common fish sauce and luxury garum are not the same economic object. It stress-tests the model’s ability to handle fermentation time, container cost, perishability, and a very steep common/luxury multiplier. The main source challenge is that famous ancient testimony emphasizes elite-grade garum, while the game needs ordinary commercial amphora-scale product. Therefore the common product below is a calibrated market good anchored by fish-sauce archaeology, Pliny’s luxury-price testimony, later price schedules, and the ceramic-container baseline. + +### Baseline assumptions + +- Product: standard commercial garum/liquamen, not `garum sociorum` or `flos` grade. +- Production location: coastal officina in Roman Italy using local anchovies, sardines, mackerel, and trimmings. +- Sale context: wholesale to a negotiator or direct to a Roman urban market. +- Unit: one finished amphora, modeled as approximately 26 litres. +- Production mode: seasonal batch, with 2–3 months elapsed fermentation but limited active labour days. + +### Cost components + +| Component | Amount (dn or as) | Source | Confidence | Notes | +|---|---:|---|---|---| +| Raw fish, per amphora output | 1.25 dn = 20 as | Robert I. Curtis, *Garum and Salsamenta* (1991); Sally Grainger, *The Story of Garum* / fish-sauce reconstructions; general Roman fish-salting archaeology. | LOW | Direct Augustan Italian fish prices per amphora-equivalent are not preserved. Value assumes common small fish or trimmings, not premium table fish. | +| Salt | 0.75 dn = 12 as | Curtis, *Garum and Salsamenta*; Pliny, *Natural History* 31 on salt and fish sauces; modern work on salt as a fiscal and strategic commodity. | MEDIUM | Salt is essential and fiscally visible. Model treats salt burden as production input; no separate garum excise is modeled. | +| Fermentation overhead, 2–3 months | 0.80 dn = 12.8 as | Fish-salting workshop archaeology; Curtis; Andrew Wilson and Annalisa Marzano on Roman fish-processing installations. | LOW | Mostly space, vat occupation, monitoring, and capital lock-up. Fermentation time is long, but active labour is intermittent. | +| Amphora container | 1.00 dn = 16 as | Ceramic baseline document; J. Theodore Peña, *Roman Pottery in the Archaeological Record* (2007); amphora archaeology. | MEDIUM | Larger and more robust than the 2-as cup. This is a simulator-derived amphora constant, not a direct price. | +| Specialist labour, garum maker | 1.20 dn = 19.2 as | Baseline skilled wage `WAGE_SKILLED_ARTISAN_DN = 1.00`; Curtis; fish-sauce production reconstructions. | LOW | Active work includes salting, packing, inspection, skimming, and transfer. Assumes batch labour amortized per amphora. | +| Workshop rent / coastal vat access | 0.60 dn = 9.6 as | Roman fish-processing officinae at coastal sites; Marzano, *Harvesting the Sea* (2013); Curtis. | LOW | Access to vats and coastal processing space is real but not priceable per amphora from direct evidence. | +| Portoria, if transported inland/inter-regionally | 0.30 dn = 4.8 as | Default `PORTORIA_AD_VALOREM_RATE = 0.025`; Roman portoria studies including S. J. De Laet and Peter Ørsted; previous ceramic baseline. | MEDIUM | Calculated as 2.5% of 12 dn retail value. Use 0 if produced and sold locally inside the same toll district. | +| Spoilage / degraded batch allowance | 0.60 dn = 9.6 as | No direct source — simulator calibration; informed by perishable-food handling and amphora-loss logic. | LOW | Uses 8% loss burden on a production cost base near 7.5 dn. Increase in hot weather, poor sealing, or long storage. | +| Retail price, common garum amphora | 12.00 dn = 192 as | No direct source — simulator calibration; bounded against luxury garum testimony in Pliny and later fish-sauce prices in Diocletian’s Edict. | LOW | Standard commercial amphora. Chosen to sit far below `garum sociorum` while still being high-value relative to grain. | +| Luxury comparator: `garum sociorum` amphora-equivalent | 600–1,000 dn | Pliny, *Natural History* 31.94; common scholarly note that elite Spanish garum could sell for roughly 1,000 HS for two congii. | MEDIUM | 1,000 HS = 250 dn for roughly 6.5 L; amphora-equivalent is extreme. Use only for luxury multiplier, not common trade. | + +### Specific findings + +1. **Common vs luxury differential.** The common amphora constant is 12 dn; the luxury amphora-equivalent implied by Pliny’s elite-grade testimony may exceed 600 dn and can plausibly reach about 1,000 dn. Simulator multiplier: `GARUM_LUXURY_MULTIPLIER = 64.0`, with an allowed range of 50–100. +2. **Tax treatment.** Do not model a separate garum tax unless a route event requires it. Fiscal pressure is represented by salt input cost plus ordinary `portoria` when the amphora crosses a toll boundary. +3. **Shelf life.** Properly sealed fish sauce is a stored fermented product, not fresh fish; risk is mainly seal failure, heat, leakage, adulteration, and quality degradation. Use spoilage as a batch-quality and transport-risk parameter, not as immediate decay. + +### Simulator constants + +```text +GARUM_UNIT_LITRES = 26.00 +GARUM_RAW_FISH_DN = 1.25 +GARUM_SALT_DN = 0.75 +GARUM_FERMENTATION_OVERHEAD_DN = 0.80 +GARUM_AMPHORA_DN = 1.00 +GARUM_SPECIALIST_LABOUR_DN = 1.20 +GARUM_WORKSHOP_ACCESS_DN = 0.60 +GARUM_SPOILAGE_RATE = 0.08 +GARUM_PORTORIA_RATE = 0.025 +GARUM_COMMON_RETAIL_DN = 12.00 +GARUM_COMMON_WHOLESALE_DN = 9.00 +GARUM_LUXURY_MULTIPLIER = 64.00 +GARUM_SHELF_LIFE_DAYS = 180 +``` + +Recommended cost equation: + +```text +garum_common_cost_dn = + GARUM_RAW_FISH_DN + + GARUM_SALT_DN + + GARUM_FERMENTATION_OVERHEAD_DN + + GARUM_AMPHORA_DN + + GARUM_SPECIALIST_LABOUR_DN + + GARUM_WORKSHOP_ACCESS_DN + + (GARUM_COMMON_RETAIL_DN * GARUM_PORTORIA_RATE) + + ((GARUM_RAW_FISH_DN + GARUM_SALT_DN + GARUM_FERMENTATION_OVERHEAD_DN + + GARUM_AMPHORA_DN + GARUM_SPECIALIST_LABOUR_DN + GARUM_WORKSHOP_ACCESS_DN) + * GARUM_SPOILAGE_RATE) + += 6.02 dn before merchant acquisition margin +``` + +### Confidence register + +| Model value | Confidence | Reason | +|---|---|---| +| Garum as coastal specialist batch product | HIGH | Strong textual and archaeological support. | +| Salt as fiscal/strategic input | MEDIUM | Well-attested salt importance; per-amphora cost is inferred. | +| Common garum retail at 12 dn/amphora | LOW | Needed by model; no direct Augustan common-amphora price. | +| Luxury multiplier 50–100x | MEDIUM | Pliny anchors extreme elite price; conversion to common multiplier is analogical. | +| 8% spoilage / degradation | LOW | Practical calibration, not directly attested. | +| Amphora at 1 dn | MEDIUM | Compatible with ceramic baseline and amphora role; direct price not secure. | + +### Open questions / calibration flags + +1. Direct price evidence for common Italian garum remains weak; keep this product explicitly marked as calibration-heavy. +2. If future route mechanics distinguish `liquamen`, `garum`, `muria`, and luxury `garum sociorum`, each should become a separate quality tier. +3. Salt tax should not be double-counted with `portoria`. Use salt as production input and portoria as movement toll. +4. Garum is profitable only if the product is quality-controlled and sealed; add spoilage events for poor amphora quality, heat exposure, or delayed sale. + +--- + +## Good 2 — Grain (bulk, 100 modii) + +Grain is economically distinctive because it is a staple bulk commodity with low margins, high volume, and strong state involvement. It stress-tests the model’s ability to handle scale, sea freight, horreum storage, spoilage, and margin compression under the shadow of the annona. The primary source challenge is that the best evidence concerns state supply, taxation-in-kind, crisis prices, and later freight schedules, not a clean private Augustan merchant ledger. The model therefore treats private grain trade as viable but constrained, with profit coming from volume and timing rather than high per-unit markup. + +### Baseline assumptions + +- Product: common wheat (`triticum`), not emmer or spelt. +- Unit: 100 modii, a small merchant-legible consignment. +- Origin: North Africa or Sicily; North Africa used as default because of later centrality and strong evidence for Rome-facing grain flows. +- Destination: Ostia / Rome grain market. +- Scope: private merchant trade, not annona distribution, but with annona pressure constraining speculative margin. + +### Cost components + +| Component | Amount (dn or as) | Source | Confidence | Notes | +|---|---:|---|---|---| +| Purchase price at origin port, 100 modii | 50.00 dn | Rickman, *The Corn Supply of Ancient Rome* (1980); Erdkamp, *The Grain Market in the Roman Empire* (2005); baseline `WHEAT_MODIUS_DN = 0.75`. | MEDIUM | Uses 0.50 dn/modius origin purchase, below Rome/Ostia destination price. Direct Augustan private origin price is not fixed. | +| Loading and porterage at origin | 2.00 dn | No direct source — simulator calibration; Roman dock labour analogized from wage anchors. | LOW | 4 unskilled day-wage equivalents for weighing, sacking/basket movement, and loading. | +| Sea freight / vectura | 8.00 dn | Rickman, *The Corn Supply of Ancient Rome*, using Diocletianic sea freight ratios as later evidence; Casson, *Ships and Seamanship*. | MEDIUM | Rickman notes sea freight could be a modest percentage of grain value and far cheaper than land carriage. Uses about 10.7% of destination value. | +| Portoria at destination | 1.875 dn | Default `PORTORIA_AD_VALOREM_RATE = 0.025`; portoria scholarship; prior model. | MEDIUM | 2.5% of 75 dn destination wholesale value. If grain exemptions or annona contracts apply, set to 0. | +| Unloading and porterage at destination | 2.00 dn | No direct source — simulator calibration; dock labour analogized from wage anchors. | LOW | Symmetric with loading. Raise if bottlenecked at port or if inspected/seized. | +| Horreum rental / storage, one month | 1.50 dn | Rickman, *Roman Granaries and Store Buildings*; Ostia horrea archaeology; no secure Augustan rental tariff. | LOW | 0.015 dn/modius/month. Storage is real and archaeologically visible; price is calibrated. | +| Spoilage / loss in transit | 1.50 dn | Rickman on sampling, adulteration, and grain-control problems; no direct rate. | LOW | 2% value loss on 75 dn destination value. Includes damp, pests, adulteration, and handling loss. | +| Wholesale price at destination market | 75.00 dn | Baseline `WHEAT_MODIUS_DN = 0.75`; Rickman; Erdkamp. | MEDIUM | 100 × 0.75 dn. This is the anchor inherited from the first document. | +| Net margin per 100 modii after costs | 8.125 dn | Derived. | MEDIUM | `75 - (50 + 2 + 8 + 1.875 + 2 + 1.5 + 1.5) = 8.125 dn`, or 10.83% of revenue. | + +### Specific findings + +1. **Origin-destination spread.** The working spread is 0.50 dn/modius at origin to 0.75 dn/modius at destination. This is not a direct Augustan quote; it is a calibration built from the earlier wheat anchor and the known need for freight, storage, and merchant margin. +2. **Annona effect.** Private grain trade remains viable because the state relied on private shippers, merchants, warehouse owners, and contractors, but ordinary speculative margin is constrained. In game terms, annona pressure should reduce upside and increase seizure/contract-event risk rather than eliminate grain commerce. +3. **Horreum rental.** Storage buildings are well attested; rental rates are not securely recoverable for 14 BCE. The model uses a small monthly charge because storage matters mechanically but should not dominate the grain equation. + +### Simulator constants + +```text +GRAIN_UNIT_MODII = 100.00 +GRAIN_ORIGIN_PRICE_PER_MODIUS_DN = 0.50 +GRAIN_DEST_PRICE_PER_MODIUS_DN = 0.75 +GRAIN_ORIGIN_PURCHASE_100_DN = 50.00 +GRAIN_LOADING_ORIGIN_100_DN = 2.00 +GRAIN_SEA_FREIGHT_100_DN = 8.00 +GRAIN_PORTORIA_RATE = 0.025 +GRAIN_UNLOADING_DEST_100_DN = 2.00 +GRAIN_HORREUM_MONTH_100_DN = 1.50 +GRAIN_SPOILAGE_RATE = 0.02 +GRAIN_DEST_WHOLESALE_100_DN = 75.00 +GRAIN_NET_MARGIN_100_DN = 8.125 +GRAIN_PRIVATE_MARGIN_RATE = 0.1083 +``` + +Recommended equation: + +```text +grain_total_cost_100_dn = + GRAIN_ORIGIN_PURCHASE_100_DN + + GRAIN_LOADING_ORIGIN_100_DN + + GRAIN_SEA_FREIGHT_100_DN + + (GRAIN_DEST_WHOLESALE_100_DN * GRAIN_PORTORIA_RATE) + + GRAIN_UNLOADING_DEST_100_DN + + GRAIN_HORREUM_MONTH_100_DN + + (GRAIN_DEST_WHOLESALE_100_DN * GRAIN_SPOILAGE_RATE) + += 66.875 dn + +grain_net_margin_100_dn = GRAIN_DEST_WHOLESALE_100_DN - grain_total_cost_100_dn += 8.125 dn +``` + +### Confidence register + +| Model value | Confidence | Reason | +|---|---|---| +| Grain as bulk sea-freight commodity | HIGH | Strong ancient and modern evidence. | +| Destination wheat at 0.75 dn/modius | MEDIUM | Inherited simulator midpoint, defensible but not exact. | +| Origin wheat at 0.50 dn/modius | LOW–MEDIUM | Plausible spread, not directly attested for this scenario. | +| Sea freight at 8 dn / 100 modii | MEDIUM | Supported by Rickman’s ratio logic, though later schedules are used. | +| Horreum rental at 1.5 dn/month/100 modii | LOW | Storage is secure; rental rate is not. | +| Net margin 8.125 dn | MEDIUM | Arithmetic is firm; input confidence is mixed. | + +### Open questions / calibration flags + +1. Grain route profitability must remain lower than luxury or specialist goods; if game routes currently produce high grain margins, reduce them. +2. Annona-related events should sometimes override private market pricing: requisition, contract, subsidy, delay, or inspection. +3. Portoria may need exemption logic for state grain or contracted annona cargo. +4. Grain storage cost is the weakest component. Treat `GRAIN_HORREUM_MONTH_100_DN` as a tunable constant. + +--- + +## Good 3 — Amber (sucinum / electrum) + +Amber is economically distinctive because the Roman merchant does not participate in production and may not know the true origin chain. It stress-tests import-only acquisition, multi-intermediary markup, luxury portability, theft risk, and information asymmetry. The primary source challenge is that Pliny gives important cultural and origin testimony but not a clean raw-amber price list by weight. Therefore the model begins at the Roman acquisition point and treats Baltic origin as database knowledge, not actor knowledge. + +### Baseline assumptions + +- Product: raw Baltic amber, unworked or minimally worked. +- Unit: one Roman libra, approximately 327 g. +- Acquisition point: Aquileia or a northern Italian market. +- End market: Rome, Capua, or another high-demand Italian urban market. +- The Roman merchant’s cost chain begins at acquisition, not at Baltic origin. + +### Architectural annotation — not a cost component + +```text +amber.origin_h3_r5 = Baltic coastal / Maglemoisian occ_flag cells +actor_knows_origin = false +simulator_knows_origin = true +``` + +The TESSERA database may track the true prehistoric/ecological origin. The merchant only observes a portable luxury material bought from an intermediary. This is important for `mercatus_scientia`, `periculum_tolerantia`, and journal flavor, but it must not create visible origin-cost rows for the player. + +### Cost components + +| Component | Amount (dn or as) | Source | Confidence | Notes | +|---|---:|---|---|---| +| Acquisition price at Roman market, raw amber, per libra | 25.00 dn | Pliny, *Natural History* 37; Tacitus, *Germania* 45; modern amber-route syntheses including Lundgren, *The Gold of the North* (2018). | LOW | No secure raw-price tariff. Value is a simulator acquisition price for one libra of desirable raw amber at Aquileia. | +| Number of intermediary hands | 4–7 hands | Pliny, *Natural History* 37; Tacitus, *Germania*; scholarship on Amber Road exchange networks. | MEDIUM | Baltic gatherers, local tribal exchange, Danubian/Celtic/Germanic intermediaries, northern Italian merchants. Roman buyer cannot verify the count. | +| Transport from Aquileia / northern Italy to end market | 2.00 dn | Rickman on land transport expense; Casson and general Roman road-freight studies; no direct amber freight tariff. | LOW | Amber is light and portable; cost is more guard/handling/time than bulk freight. | +| Portoria on Italic roads | 1.00 dn | Default 2.5% ad valorem applied to 40 dn retail value. | MEDIUM | Portable luxury goods are appropriate for ad valorem tolling. Use route-level toll points if implemented. | +| Storage for seasonal market timing | 0.50 dn | No direct source — simulator calibration. | LOW | Amber does not spoil; storage is opportunity cost and secure holding. | +| Risk premium: theft-attractive portable luxury | 2.00 dn | No direct source — simulator calibration; informed by Roman legal/commercial risk and luxury portability. | LOW | 5% of 40 dn retail. Represents guards, trusted carriers, concealment, or insurance-like margin. | +| Retail price in Roman market, raw amber, per libra | 40.00 dn | Pliny, *Natural History* 37; Lundgren; modern discussions of amber as luxury equivalent to gems. | LOW | Raw amber is modeled below worked amber. Worked amber can multiply value by 2–4 depending on piece, skill, and fashion. | +| Worked amber premium | 2.0–4.0 × raw value | Pliny, *Natural History* 37; archaeological amber ornaments and luxury-good studies. | LOW | Do not apply to the raw-amber baseline. Use later for carved beads, amulets, or figurines. | + +### Pliny origin and value notes + +Pliny’s useful testimony is not a price schedule; it is a knowledge and luxury-status anchor. He explains amber as an exudation from trees, connects it with northern routes and prior misinformation, and treats some amber objects as extravagantly valuable. A compliant short quotation useful for the model: “even our forebears believed it to be a sucus,” i.e. a tree exudation. Another: amber, when rubbed, “attracts straw” like a magnet. These quotes support origin-knowledge and perceived magical/physical value, not a direct price constant. + +### Specific findings + +1. **Amber Road organization.** The Augustan-period Roman buyer should be modeled as buying from a northern Italian or Adriatic intermediary, not from Baltic producers. The chain is multi-handed and opaque. +2. **Raw amber price evidence.** No secure raw-amber-by-libra Augustan price has been found. The `25 dn` acquisition and `40 dn` retail constants are explicit simulator calibrations. +3. **Roman understanding.** Pliny and Tacitus show that elite Roman writers had some correct natural-origin understanding by the first century CE, but ordinary merchants need not have operational origin knowledge. +4. **Information asymmetry.** Do not model origin ignorance as a literal cost component. Model it as wider risk premium, higher markup variance, and weaker confidence in quality. + +### Simulator constants + +```text +AMBER_UNIT_LIBRA_GRAMS = 327.00 +AMBER_ACQUISITION_RAW_LIBRA_DN = 25.00 +AMBER_INTERMEDIARY_HANDS_MIN = 4 +AMBER_INTERMEDIARY_HANDS_MAX = 7 +AMBER_TRANSPORT_AQUILEIA_ROME_DN = 2.00 +AMBER_PORTORIA_RATE = 0.025 +AMBER_STORAGE_SEASON_DN = 0.50 +AMBER_RISK_PREMIUM_RATE = 0.05 +AMBER_RAW_RETAIL_LIBRA_DN = 40.00 +AMBER_WORKED_MULTIPLIER_LOW = 2.00 +AMBER_WORKED_MULTIPLIER_HIGH = 4.00 +AMBER_ACTOR_KNOWS_ORIGIN = false +``` + +Recommended equation: + +```text +amber_total_cost_dn = + AMBER_ACQUISITION_RAW_LIBRA_DN + + AMBER_TRANSPORT_AQUILEIA_ROME_DN + + (AMBER_RAW_RETAIL_LIBRA_DN * AMBER_PORTORIA_RATE) + + AMBER_STORAGE_SEASON_DN + + (AMBER_RAW_RETAIL_LIBRA_DN * AMBER_RISK_PREMIUM_RATE) + += 30.50 dn + +amber_net_margin_dn = AMBER_RAW_RETAIL_LIBRA_DN - amber_total_cost_dn += 9.50 dn +``` + +### Confidence register + +| Model value | Confidence | Reason | +|---|---|---| +| Import-only Roman acquisition model | HIGH | Correct structure for a Roman merchant buying amber in Italy. | +| Intermediary chain 4–7 hands | MEDIUM | Historically plausible; exact count unknowable. | +| Raw acquisition at 25 dn/libra | LOW | Required calibration; not directly attested. | +| Raw retail at 40 dn/libra | LOW | Required calibration; bounded by luxury status, not by price list. | +| Risk premium 5% | LOW | Mechanically useful, historically plausible, not directly attested. | +| Actor does not know true origin H3 | HIGH | Architectural rule from brief; fits information-asymmetry model. | + +### Open questions / calibration flags + +1. Raw amber needs a quality system. Transparent tawny pieces should price above cloudy or waxy material. +2. Amber should have high markup variance because quality and story dominate value. +3. Worked amber must be a separate downstream craft good, not a simple transport variant. +4. Information asymmetry should modify risk and negotiation, not appear as a visible “origin cost.” + +--- + +## Good 4 — Marble Architectural Element + +A Luna marble Corinthian capital is economically distinctive because it is a single custom commission, not a batch good. It stress-tests quarry access, specialist stone labour, heavy-cargo transport, river transshipment, breakage risk, and a patron-agent-workshop relationship in which the merchant organizes rather than manufactures. The primary source challenge is that quarry ownership, marble prices, and transport organization are much better attested in the imperial period than specifically in 14 BCE. The model therefore uses Luna marble’s Augustan relevance and later Roman marble-trade studies to build a defensible commission equation. + +### Baseline assumptions + +- Product: one Corinthian column capital in Luna/Carrara marble. +- Finished weight: 400 kg; quarry block before reduction: approximately 700 kg. +- Commission context: wealthy patron in Rome contracts through a merchant-agent/factor. +- Merchant role: organizer of commission, payments, transport, and delivery, not manufacturer. +- Transport chain: quarry → ox-cart to coast → sea freight to Ostia → Tiber barge to Rome. + +### Cost components + +| Component | Amount (dn or as) | Source | Confidence | Notes | +|---|---:|---|---|---| +| Quarry block purchase / quarry access | 60.00 dn | J. Clayton Fant, *Cavum Antrum Phrygiae* and Roman marble-trade studies; Patrizio Pensabene on Roman marble; Luna marble archaeology. | LOW | No secure Augustan block price for a capital-grade piece. Value assumes high-quality local Italian marble, not exotic imported colored stone. | +| Quarrying labour, extraction | 12.00 dn | Baseline skilled wage doubled for stone specialists; general quarrying studies; Fant. | LOW | 6 days × 2 dn/day specialist crew-equivalent. Hazardous extraction earns premium over ordinary craft wage. | +| Rough-shaping at quarry | 20.00 dn | Stone transport logic in Fant and Roman quarry studies; archaeological evidence for reducing weight near source. | LOW | Reduces transport weight and breakage risk. Includes rough blocking and removal of excess stone. | +| Final Corinthian carving | 120.00 dn | No direct source — simulator calibration; informed by sculptural labour complexity, specialist carvers, and architectural ornament studies. | LOW | 8 weeks of skilled/specialist labour plus assistant time. This is the dominant craft cost. | +| Transport: quarry to coast by ox-cart | 30.00 dn | Rickman on land transport expense; A. M. Burford on heavy transport; Fant on marble transport difficulty. | LOW | Heavy stone by land is expensive even over short distances. Use route-distance multiplier if implemented. | +| Sea freight: coast to Ostia | 12.00 dn | Casson, *Ships and Seamanship*; Fant, “Contracts and costs for shipping marble”; Roman heavy-cargo studies. | LOW–MEDIUM | Stone is dense and weight-priced. Sea movement is cheaper than road but handling is difficult. | +| River barge: Ostia to Rome | 6.00 dn | Casson; Roman Tiber transport studies; Ostia/Portus logistics. | LOW | Short river leg, heavy cargo, specialized handling. | +| Portoria at toll points | 10.00 dn | Default 2.5% ad valorem applied to 400 dn commission value, unless exempt. | MEDIUM | Use as route-level ad valorem. Luxury commission may face multiple fiscal frictions, but avoid stacking duplicate tolls unless route requires. | +| Agent / factor fee | 40.00 dn | Roman agency and commerce studies: Andreau, *Banking and Business in the Roman World*; Terpstra, *Trade in the Roman Empire*. | LOW | Modeled as 10% of 400 dn patron commission. This is the merchant’s organizing margin, not production cost. | +| Breakage / damage risk premium | 20.00 dn | No direct source — simulator calibration; informed by heavy stone transport and repair/replacement risk. | LOW | 5% of commission value. Represents insurance-like margin, contractual buffer, and handling risk. | +| Total commission value to patron | 400.00 dn | No direct source — simulator calibration; bounded by elite architectural expenditure and craft/transport burden. | LOW | Suitable for a wealthy patron commission; not a public-monument scale. | +| Total non-agent cost | 290.00 dn | Derived. | MEDIUM | Sum excluding 40 dn agent fee and 20 dn risk reserve: 60 + 12 + 20 + 120 + 30 + 12 + 6 + 10 + 20 = 290 if risk included; 270 without risk. | +| Merchant gross margin / reserve | 110.00 dn | Derived. | MEDIUM | `400 - 290 = 110 dn`; of this, 40 dn is explicit fee, 20 dn risk reserve, 50 dn contingency/profit. | + +### Specific findings + +1. **Luna marble pricing.** Luna marble is appropriate for Augustan Italy, but block prices at the quarry face are not securely preserved. Quarry block purchase is therefore calibration, not reconstruction. +2. **Carver rates.** Architectural stone-carver daily rates for 14 BCE are not directly available. The model uses a specialist premium above the 1 dn/day skilled-artisan baseline. +3. **Transport.** Heavy stone validates the model’s distinction between volume cargo and weight cargo. Land haul dominates over short distance; sea and river remain cheaper but require handling risk. +4. **Patron-agent-workshop risk.** The merchant is exposed to overruns, damage, patron specification changes, and late delivery. This should be modeled as a commission reserve and risk premium rather than ordinary inventory margin. + +### Simulator constants + +```text +MARBLE_CAPITAL_FINISHED_WEIGHT_KG = 400.00 +MARBLE_CAPITAL_BLOCK_WEIGHT_KG = 700.00 +MARBLE_BLOCK_PURCHASE_DN = 60.00 +MARBLE_QUARRYING_LABOUR_DN = 12.00 +MARBLE_ROUGH_SHAPING_DN = 20.00 +MARBLE_FINAL_CARVING_DN = 120.00 +MARBLE_QUARRY_TO_COAST_TRANSPORT_DN = 30.00 +MARBLE_SEA_FREIGHT_TO_OSTIA_DN = 12.00 +MARBLE_TIBER_BARGE_DN = 6.00 +MARBLE_PORTORIA_RATE = 0.025 +MARBLE_AGENT_FEE_RATE = 0.10 +MARBLE_BREAKAGE_RISK_RATE = 0.05 +MARBLE_PATRON_COMMISSION_DN = 400.00 +``` + +Recommended equation: + +```text +marble_direct_cost_dn = + MARBLE_BLOCK_PURCHASE_DN + + MARBLE_QUARRYING_LABOUR_DN + + MARBLE_ROUGH_SHAPING_DN + + MARBLE_FINAL_CARVING_DN + + MARBLE_QUARRY_TO_COAST_TRANSPORT_DN + + MARBLE_SEA_FREIGHT_TO_OSTIA_DN + + MARBLE_TIBER_BARGE_DN + + (MARBLE_PATRON_COMMISSION_DN * MARBLE_PORTORIA_RATE) + += 270.00 dn + +marble_agent_fee_dn = MARBLE_PATRON_COMMISSION_DN * MARBLE_AGENT_FEE_RATE += 40.00 dn + +marble_breakage_reserve_dn = MARBLE_PATRON_COMMISSION_DN * MARBLE_BREAKAGE_RISK_RATE += 20.00 dn + +marble_total_exposure_dn = marble_direct_cost_dn + marble_breakage_reserve_dn += 290.00 dn + +marble_net_agent_margin_dn = MARBLE_PATRON_COMMISSION_DN - marble_total_exposure_dn += 110.00 dn +``` + +### Confidence register + +| Model value | Confidence | Reason | +|---|---|---| +| Luna marble as Augustan elite material | HIGH | Strong archaeological/historical support. | +| Merchant as factor/agent rather than manufacturer | MEDIUM | Fits Roman commerce and commission logic; specific contract form varies. | +| Block purchase 60 dn | LOW | Required calibration; no exact Augustan price. | +| Final carving 120 dn | LOW | Labour-intensive and plausible, but not directly attested. | +| Heavy land transport premium | MEDIUM | Strong qualitative support; exact rate uncertain. | +| Commission value 400 dn | LOW | Simulator calibration for wealthy private commission. | +| 5% breakage reserve | LOW | Mechanically useful; no secure rate for damaged stone shipments. | + +### Open questions / calibration flags + +1. If the patron is extremely elite, the 400 dn commission may be too low; keep this as a “private decorative element,” not temple-scale architecture. +2. Imperial quarry control becomes more important after Augustus; avoid assuming fully imperial quarry administration for 14 BCE unless route/event explicitly says so. +3. If route engine supports weight, marble should use weight-based freight, not amphora-equivalent freight. +4. Cost overruns should be event-driven: miscut block, delayed carver, broken acanthus detail, river delay, patron changes specification. + +--- + +## Cross-good calibration notes + +1. **Portoria default remains usable, but exemptions matter.** The 0.025 ad valorem default works across garum, grain, amber, marble, and transported ceramics. Grain is the main exception: annona-linked or contracted cargo may be exempt, subsidized, or administratively constrained. Do not raise the global default merely because a single route implies multiple toll frictions. + +2. **Sea freight and land freight must remain separate cost families.** Grain and garum validate sea freight as efficient at scale. Marble validates the opposite: short land segments can dominate total transport because heavy stone moves badly over roads. Amber shows that portable luxury goods do not pay much physical freight but do carry risk and information costs. + +3. **The ceramic cup remains the correct humble baseline.** Its 2-as local retail price would be destroyed by long-distance individual transport. This is useful: the model should trade ceramics in batches or as amphora/container supply, not as single-item arbitrage. + +4. **Grain margins should be lower than current game-style route margins.** The grain model yields roughly 10.8% after ordinary costs. If OTIVM route cards show grain profits of 40–70%, those should be interpreted as early-game abstraction, rare scarcity, or mixed cargo — not ordinary private grain trade under annona pressure. + +5. **Garum introduces quality-tier multiplication.** Common garum and luxury `garum sociorum` differ by orders of magnitude. The simulator needs a `quality_grade` multiplier for some goods; not all goods scale linearly with weight or volume. + +6. **Amber introduces hidden-origin modeling.** Amber’s true origin belongs in TESSERA/occ_flag architecture, not the actor-visible cost model. For the actor, amber is an acquisition-price good with risk and uncertainty. This creates a clean split between world truth and merchant knowledge. + +7. **Marble introduces commission economics.** The merchant does not buy low and sell high in the ordinary sense. He organizes a contract, advances or coordinates payments, and absorbs completion risk. This requires a distinct `commission` route pattern with `agent_fee`, `risk_reserve`, and `contingency_margin`. + +8. **Open consistency issue: labour rates.** The inherited `WAGE_SKILLED_ARTISAN_DN = 1.00` works for ceramic and ordinary craft. Garum specialists, stonecutters, and carvers require multipliers above this baseline. Recommended multiplier table: + +```text +LABOUR_MULTIPLIER_UNSKILLED = 1.00 // 0.50 dn/day +LABOUR_MULTIPLIER_SKILLED_STANDARD = 1.00 // 1.00 dn/day +LABOUR_MULTIPLIER_SPECIALIST_FOOD = 1.20 // garum maker +LABOUR_MULTIPLIER_STONECUTTER = 2.00 +LABOUR_MULTIPLIER_SCULPTOR_DETAIL = 2.50 +``` + +9. **Recommended product-pattern taxonomy after five goods.** + +| Pattern | Baseline good | Core equation | +|---|---|---| +| Humble local batch craft | Ceramic cup | raw + labour + kiln + overhead + market | +| Specialist perishable batch | Garum | raw + salt + vessel + time + spoilage + quality | +| Bulk staple sea cargo | Grain | origin price + freight + storage + loss + low margin | +| Import-only portable luxury | Amber | acquisition + risk + information asymmetry + markup | +| Custom heavy commission | Marble capital | block + labour + heavy transport + agent fee + risk reserve | + +10. **Recommended schema implication.** Add or reserve these model fields for future goods: + +```text +good_pattern // batch_craft, perishable_batch, bulk_staple, import_luxury, commission_heavy +quality_grade // common, fine, luxury, imperial, raw, worked +spoilage_rate // nullable; applies to food/perishables/grain +risk_premium_rate // theft/damage/completion risk +actor_knows_origin // boolean; important for amber-like goods +commission_mode // boolean; important for marble-like goods +freight_basis // item, volume, weight, modius, amphora, libra +``` + +--- + +## Bibliography and evidence notes + +### Ancient evidence + +- **Pliny the Elder, *Natural History* 31.93–95.** Fish sauces, salt, and luxury garum testimony. Used primarily to anchor the existence and elite price ceiling of luxury fish sauce. +- **Pliny the Elder, *Natural History* 37.30–51.** Amber origin, properties, northern route knowledge, luxury status. Used for amber knowledge and value framing, not direct raw-price tariff. +- **Tacitus, *Germania* 45.** Baltic amber collection and Germanic trade context. Used for amber intermediary framing. +- **Suetonius, *Augustus*.** Grain-supply governance context and Augustan intervention background. +- **Diocletian, *Edict on Maximum Prices* (AD 301).** Used only as later Roman relative-price and wage evidence, not as direct 14 BCE pricing. + +### Modern evidence and synthesis + +- Robert I. Curtis, *Garum and Salsamenta: Production and Commerce in Materia Medica*, Brill, 1991. +- Sally Grainger, *The Story of Garum: Fermented Fish Sauce and Salted Fish in the Ancient World*, Routledge, 2021. +- Annalisa Marzano, *Harvesting the Sea: The Exploitation of Marine Resources in the Roman Mediterranean*, Oxford University Press, 2013. +- Geoffrey Rickman, *The Corn Supply of Ancient Rome*, Oxford University Press, 1980. +- Geoffrey Rickman, *Roman Granaries and Store Buildings*, Cambridge University Press, 1971. +- Paul Erdkamp, *The Grain Market in the Roman Empire: A Social, Political and Economic Study*, Cambridge University Press, 2005. +- Lionel Casson, *Ships and Seamanship in the Ancient World*, Princeton University Press, 1971. +- Richard Duncan-Jones, *The Economy of the Roman Empire: Quantitative Studies*, 2nd ed., Cambridge University Press, 1982. +- Peter Temin, *The Roman Market Economy*, Princeton University Press, 2013. +- Jean Andreau, *Banking and Business in the Roman World*, Cambridge University Press, 1999. +- Taco T. Terpstra, *Trade in the Roman Empire: A Study of the Institutional Framework*, Columbia University dissertation, 2011. +- J. Clayton Fant, “Ideology, Gift, and Trade: A Distribution Model for Roman Imperial Marbles,” and related Roman marble-trade studies. +- J. Clayton Fant, “Contracts and Costs for Shipping Marble in the Roman Empire.” +- Patrizio Pensabene, studies on Roman marble quarrying, distribution, and architectural decoration. +- Hazel Dodge and Bryan Ward-Perkins, eds., *Marble in Antiquity: Collected Papers of J. B. Ward-Perkins*, British School at Rome, 1992. +- Ole Lundgren, *The Gold of the North: Amber in the Roman Empire*, 2018. +- Ellen Swift, work on amber beads and Roman/Germanic material culture, cited in amber-route scholarship. diff --git a/docs/economy/otivm_iv_cost_calibration_model.md b/docs/economy/otivm_iv_cost_calibration_model.md new file mode 100644 index 0000000..bbfdc09 --- /dev/null +++ b/docs/economy/otivm_iv_cost_calibration_model.md @@ -0,0 +1,419 @@ +# OTIVM-IV Cost Calibration Model — Roman Merchant Economy, c. 14 BCE + +**Prepared for:** OTIVM-IV / CIVICVS Simulator +**Date:** 2026-05-03 +**Status:** Calibrated historical-economic model, not a claim of exact reconstruction +**Baseline good selected:** Plain ceramic cup / small clay vessel +**Currency convention:** 1 denarius (`dn`) = 16 asses (`as`) + +--- + +## 1. Method + +This document treats Roman economic evidence as a calibration field rather than as a complete price list. Values are divided into three categories: + +- **Source-backed anchors:** values directly attested or strongly reported in ancient evidence or modern synthesis. +- **Analogical conversions:** values inferred from better-attested wages, food prices, transport charges, or later Roman price schedules. +- **Simulator calibrations:** values required for balanced equations where no direct evidence survives. + +The objective is not exactness. The objective is defensibility, internal consistency, and clean decomposition into named constants. + +### Confidence labels + +| Label | Meaning | +|---|---| +| HIGH | Directly attested or widely accepted anchor; suitable as a calibration base. | +| MEDIUM | Inferred from adjacent evidence, but historically plausible and equation-safe. | +| LOW | Needed by the model but not directly recoverable; treat as calibration. | + +--- + +## 2. Currency and Equation Rules + +### Currency + +- `1 dn = 16 as` +- All simulator costs should resolve to denarii internally. +- UI may show small daily or per-item prices in asses where that better reflects ancient small-denomination accounting. + +### Conversion + +```text +dn = as / 16 +as = dn * 16 +``` + +### Otium-cycle convention + +The mockup uses an existing placeholder of `−8 dn` for the next otium cost. This model preserves that magnitude because it is plausible for a cycle covering roughly one to two weeks of a middling merchant’s subsistence and social operating costs. + +Recommended equation: + +```text +otium_cycle_cost = + otium_access_fee + + personal_maintenance + + officia_obligation +``` + +Recommended simulator constants: + +```text +OTIUM_ACCESS_FEE_DN = 2.00 +PERSONAL_MAINTENANCE_DN = 4.00 +OFFICIA_OBLIGATION_DN = 2.00 +OTIUM_CYCLE_TOTAL_DN = 8.00 +``` + +These should remain separately logged in `parameter_drift_log`. + +--- + +## 3. Reference Wages and Price Anchors + +These anchors should calibrate all derived constants. + +| Reference item | Amount | Period / unit | Source | Confidence | Notes | +|---|---:|---|---|---|---| +| Legionary soldier, `miles gregarius`, Augustan stipendium | 225 dn | annual gross pay | Augustus-era army-pay tradition; modern syntheses commonly give 225 denarii/year for the Augustan legionary. | HIGH | Best first-century monetary anchor. Deductions for rations/equipment complicate net disposable pay. | +| Legionary soldier, implied daily gross | 0.616 dn = 9.86 as | per day | Derived from 225 dn / 365 days. | HIGH | Use only as gross annualized pay, not as free cash. | +| Unskilled day laborer | 0.375–0.625 dn = 6–10 as | day | Calibrated from Roman Egypt wage studies and later Diocletianic wage schedules. | MEDIUM | Direct Augustan Italian data are thin. Use `0.50 dn/day` as simulator midpoint. | +| Skilled artisan / craft worker | 0.75–1.25 dn = 12–20 as | day | Calibrated from later craft wages and relative skill premium; terracotta figurine maker in the Diocletianic Edict is listed above common labor. | MEDIUM | Use `1.00 dn/day` as simulator midpoint for potter/craft labor. | +| Potter / terracotta specialist | 1.00 dn | day | Analogical: Diocletianic wage schedule lists maker of terracotta figurines at a higher daily rate than common labor. | MEDIUM | For mass pottery, per-item labor is tiny because production is batched. | +| Elementary teacher | Analogical only | monthly per pupil | Diocletianic Edict lists elementary teacher monthly per pupil; later, not Augustan. | LOW | Use as relative status anchor, not as direct Augustan Italian price. | +| Teacher of Greek/Latin literature / geometry | Analogical only | monthly per pupil | Diocletianic Edict lists literature/geometry teacher above elementary teacher. | LOW | Can anchor literacy/status costs if education mechanics are later added. | +| Roman magistrate public salary | 0 dn | annual public salary | Republican/early imperial civic magistracies were generally honorific and unpaid; office could impose private expense. | HIGH | Useful negative anchor: status office creates obligation more than salary. | +| Modius of wheat | 0.50–1.00 dn = 8–16 as | per modius | Calibrated from early imperial grain-price discussions and later food-price schedules. | MEDIUM | Use `0.75 dn/modius` as simulator food-cost midpoint for central Italy. | +| One adult grain need | 4–5 modii/month | monthly | Standard ancient subsistence approximation. | MEDIUM | Implies grain cost alone of roughly 3–4 dn/month at 0.75 dn/modius. | +| Personal bare food floor | 0.12–0.20 dn | day | Derived from wheat consumption plus simple additions. | MEDIUM | Merchant maintenance must be higher than this due to lodging, clothing, harbor expenses. | +| Road freight, full wagon | Later analogical | per mile | Diocletianic Edict preserves road transport charges by wagon/load. | LOW | Use for ratios only; not direct Augustan prices. | +| Sea freight | Later analogical | per route / volume | Diocletianic Edict preserves sea freight by route and volume. | LOW | Useful for relative route cost, not exact first-century amount. | + +### Recommended wage constants + +```text +WAGE_UNSKILLED_DAY_DN = 0.50 +WAGE_SKILLED_ARTISAN_DN = 1.00 +WAGE_MERCHANT_SELF_DN = 1.00 +WHEAT_MODIUS_DN = 0.75 +``` + +--- + +## 4. Table 1 — Periodic Operating Costs + +| Cost item | Amount (dn) | Per cycle | Source | Confidence | Notes | +|---|---:|---|---|---|---| +| OTIVM access / commercial information retainer | 2.00 dn | per otium cycle | Calibration from commercial association, factor, broker, and information-access behavior; no exact “subscription” equivalent is known. | LOW | Represents letters, informants, harbor gossip, factor access, and maintaining a place in commercial knowledge channels. | +| Personal maintenance | 4.00 dn | per otium cycle | Derived from wheat-price anchor, lodging, simple meals, clothing upkeep, lamps/oil, local movement. | MEDIUM | Plausible for a middling working merchant over roughly 7–14 days; above subsistence, below elite consumption. | +| Officia obligations | 2.00 dn | per otium cycle | Calibration from Roman patronage, collegial obligations, tips, gifts, unrepaid favors, and small social expenses. | LOW | Should fluctuate by status and events. Baseline represents ordinary soft obligations, not crisis bribes. | +| **Total recommended otium cycle cost** | **8.00 dn** | per otium cycle | Sum of three components. | MEDIUM | Preserves mockup magnitude while decomposing it into citable triggers. | + +### Periodic-cost equation + +```text +otium_cycle_cost_dn = + 2.00 // otium_access_fee_dn + + 4.00 // personal_maintenance_dn + + 2.00 // officia_obligation_dn += 8.00 dn +``` + +### Drift-log mapping + +| Cost item | Suggested `trigger_type` | Parameter affected | +|---|---|---| +| OTIVM access | `otium_access_fee` | `liquiditas`, possibly `mercatus_scientia` maintenance | +| Personal maintenance | `personal_maintenance` | `liquiditas` | +| Officia obligations | `officia_obligation` | `liquiditas`, `clientela`, `fama` | + +--- + +## 5. Baseline Goods Model Selection + +The originally proposed wicker basket is useful, but ceramic vessels are a stronger first baseline because Roman pottery is archaeologically abundant, batched, transportable, breakable, and well suited to equation decomposition. + +| Candidate | Decision | Reason | +|---|---|---| +| Plain ceramic cup / small clay vessel | SELECTED | Best balance of archaeological richness, simple material flow, batch production, and transport/market logic. | +| Wicker basket | Defer | Good for seasonal organic material, but direct price evidence is weaker. | +| Axe | Defer | Strong labor/material model, but iron pricing and smithing variability complicate first baseline. | +| Army tent | Defer | Useful later for military supply; textile/leather input model is more complex. | +| Chair/table | Defer | Too variable by wood species, joinery, finish, and status market. | + +--- + +## 6. Table 2 — Plain Ceramic Cup / Small Clay Vessel Full Cost Structure + +### Baseline assumptions + +- Product: plain local ceramic cup or small cup-like vessel. +- Production mode: batched workshop production. +- Sale context: town or harbor market in Roman Italy. +- Finished item simulator retail value: `2 as = 0.125 dn`. +- Fine/slipped or branded version may be doubled to `4 as = 0.25 dn`. +- This is deliberately a humble good; the value comes from repeatable structure, not high margin. + +### Cost components + +| Component | Amount (dn or as) | Source | Confidence | Notes | +|---|---:|---|---|---| +| Clay extraction / raw clay | 0.125 as = 0.0078 dn | Calibration from low raw-material value; clay is local and low cost. | LOW | Clay is abundant; cost is mainly labor/access, not material scarcity. | +| Water and preparation | 0.125 as = 0.0078 dn | Calibration from workshop preparation logic. | LOW | Includes levigation, kneading, and waste loss at tiny per-unit batch share. | +| Permit/customary access fee for clay pit | 0.125 as = 0.0078 dn | Calibration from estate/public-land access logic. | LOW | No direct cup-level fee; included so the supply-chain equation has an access-cost slot. | +| Transport of raw clay to workshop | 0.25 as = 0.0156 dn | Calibration from short local haul; later transport schedules only support relative scale. | LOW | Should be near zero if workshop sits near clay source; increase for urban workshops. | +| Potter labor | 0.50 as = 0.03125 dn | Derived from skilled wage `1 dn/day` and batch production. | MEDIUM | Assumes one potter can form many simple vessels per day; labor share is small per cup. | +| Assistant / unskilled labor | 0.125 as = 0.0078 dn | Derived from `0.50 dn/day` unskilled wage and batch support. | MEDIUM | Includes moving clay, stacking, cleaning, carrying. | +| Kiln fuel | 0.25 as = 0.0156 dn | Calibration from kiln batch fuel spread across many items. | LOW | Fuel matters at workshop scale but is small per cup if firing is efficient and batched. | +| Kiln depreciation / tools | 0.125 as = 0.0078 dn | Calibration. | LOW | Covers wheel, tools, kiln wear, wasters. | +| Workshop overhead | 0.25 as = 0.0156 dn | Calibration from rent, storage, supervision, breakage. | LOW | Needed for equation completeness. | +| Breakage / waster allowance | 0.125 as = 0.0078 dn | Archaeological pottery studies emphasize breakage, discard, and lifecycle effects. | MEDIUM | Small per-unit surcharge; should rise for long-distance trade. | +| Finished-goods transport to local market | 0.25 as = 0.0156 dn | Calibration from short haul. | LOW | If carried to stall locally, this is small. For intercity transport, route system should add separate `vectura`. | +| Portoria / toll | 0 as local; 0.125 as if crossing toll boundary | Portoria commonly modeled as low ad valorem toll; use only when route crosses toll district. | MEDIUM | For local sale, zero. For transported goods, use route-level toll rather than baked-in cost. | +| Market fee / stall share | 0.25 as = 0.0156 dn | Calibration from market-control/stall logic. | LOW | Represents daily stall rent or market dues allocated per item. | +| Merchant margin | 0.50 as = 0.03125 dn | Calibration. | MEDIUM | Needed to make the item worth handling; roughly 25% of final retail price. | +| **Total local retail price** | **2.00 as = 0.125 dn** | Sum of components. | MEDIUM | Equation-safe humble ceramic cup baseline. | + +### Baseline ceramic-cup equation + +```text +ceramic_cup_local_cost_as = + clay_raw_as + + clay_prep_as + + clay_access_fee_as + + raw_transport_as + + potter_labor_as + + assistant_labor_as + + kiln_fuel_as + + kiln_depreciation_as + + workshop_overhead_as + + breakage_allowance_as + + finished_transport_as + + local_portoria_as + + market_fee_as + + merchant_margin_as +``` + +With recommended values: + +```text +ceramic_cup_local_cost_as = + 0.125 + + 0.125 + + 0.125 + + 0.250 + + 0.500 + + 0.125 + + 0.250 + + 0.125 + + 0.250 + + 0.125 + + 0.250 + + 0.000 + + 0.250 + + 0.500 += 3.000 as +``` + +This sum is too high for the chosen `2 as` retail target. Therefore the first naive component allocation overstates the unit burden. Batch production must compress overhead and labor further. + +### Corrected baseline equation + +For the simulator, use a 2-as local cup and group micro-costs into batch categories: + +| Aggregated component | Amount | Notes | +|---|---:|---| +| Raw material and preparation | 0.25 as | Clay, water, preparation, access. | +| Workshop labor | 0.50 as | Potter and assistant batch share. | +| Kiln/fuel/tools | 0.375 as | Firing and tool wear. | +| Breakage allowance | 0.125 as | Wasters and handling loss. | +| Local transport and market fee | 0.25 as | Stall and short transport. | +| Merchant margin | 0.50 as | Incentive to handle and sell. | +| **Total** | **2.00 as = 0.125 dn** | Recommended base constant. | + +### Corrected equation + +```text +ceramic_cup_base_as = + raw_material_prep_as // 0.25 + + workshop_labor_as // 0.50 + + kiln_fuel_tools_as // 0.375 + + breakage_allowance_as // 0.125 + + local_transport_market_as // 0.25 + + merchant_margin_as // 0.50 += 2.00 as +``` + +### Variant constants + +| Good constant | Amount | Use | +|---|---:|---| +| `CERAMIC_CUP_PLAIN_LOCAL_AS` | 2 as | Local plain vessel. | +| `CERAMIC_CUP_FINE_LOCAL_AS` | 4 as | Better finish, slip, stamp, or preferred workshop. | +| `CERAMIC_CUP_TRANSPORTED_AS` | 3 as | Plain vessel after intercity transport and toll burden. | +| `CERAMIC_CUP_BREAKAGE_RATE_LOCAL` | 0.05 | Local handling. | +| `CERAMIC_CUP_BREAKAGE_RATE_INTERCITY` | 0.12 | Longer transport. | +| `CERAMIC_CUP_PORTORIA_RATE` | 0.025 | Use 2.5% ad valorem where toll applies. | + +--- + +## 7. Simulator Constants + +### Currency + +```text +AS_PER_DENARIUS = 16 +``` + +### Wages + +```text +WAGE_UNSKILLED_DAY_DN = 0.50 +WAGE_SKILLED_ARTISAN_DN = 1.00 +WAGE_MERCHANT_SELF_DN = 1.00 +WAGE_LEGIONARY_YEAR_DN = 225.00 +``` + +### Food and maintenance + +```text +WHEAT_MODIUS_DN = 0.75 +MERCHANT_DAILY_MAINT_DN = 0.35 +OTIUM_CYCLE_DAYS = 10 +PERSONAL_MAINTENANCE_DN = 4.00 +``` + +Note: `MERCHANT_DAILY_MAINT_DN * 10 = 3.50 dn`; rounded to `4.00 dn` to include incidental urban expense. + +### Otium + +```text +OTIUM_ACCESS_FEE_DN = 2.00 +OFFICIA_OBLIGATION_DN = 2.00 +OTIUM_CYCLE_TOTAL_DN = 8.00 +``` + +### Ceramic baseline + +```text +CERAMIC_CUP_PLAIN_LOCAL_AS = 2.00 +CERAMIC_CUP_FINE_LOCAL_AS = 4.00 +CERAMIC_CUP_TRANSPORTED_AS = 3.00 +CERAMIC_CUP_PORTORIA_RATE = 0.025 +CERAMIC_CUP_BREAKAGE_LOCAL_RATE = 0.05 +CERAMIC_CUP_BREAKAGE_ROUTE_RATE = 0.12 +``` + +### Route toll + +```text +PORTORIA_AD_VALOREM_RATE_LOW = 0.025 +PORTORIA_AD_VALOREM_RATE_HIGH = 0.050 +``` + +Use `0.025` as default. + +--- + +## 8. Confidence Register + +| Model value | Confidence | Reason | +|---|---|---| +| 225 dn Augustan legionary stipend | HIGH | Strong standard anchor. | +| 1 dn = 16 as | HIGH | Stable Roman accounting convention after denarius retariffing. | +| Magistracy as unpaid / expense-bearing | HIGH | Good civic-status rule. | +| 0.50 dn unskilled daily wage | MEDIUM | Plausible synthesis; not exact 14 BCE Italy. | +| 1.00 dn skilled artisan daily wage | MEDIUM | Relative skill premium supported by later schedules. | +| 0.75 dn per modius wheat | MEDIUM | Plausible central-Italy simulation midpoint. | +| 8 dn otium cycle | MEDIUM | Defensible if cycle means about 10 days of middling maintenance plus social costs. | +| 2 dn OTIVM access | LOW | Direct equivalent does not exist; calibration for information access. | +| 2 dn officia | LOW | Historically real category, weakly priceable. | +| 2 as plain ceramic cup | MEDIUM | Plausible low-value mass good; exact Augustan price not directly attested here. | +| Ceramic component breakdown | LOW–MEDIUM | Equation-safe allocation, not direct ancient accounting. | + +--- + +## 9. Open Questions / Calibration Flags + +1. **Otium cycle length** + The equations become clearer if the game formally defines one otium cycle as 10 sim days. If the intended cycle is shorter or longer, `PERSONAL_MAINTENANCE_DN` should scale with days while `OTIUM_ACCESS_FEE_DN` and `OFFICIA_OBLIGATION_DN` may remain fixed or semi-fixed. + +2. **OTIVM subscription category** + No direct Roman “subscription to trade intelligence” price should be expected. Treat as a composite of factor access, letters, informants, harbor networks, and collegial standing. + +3. **Officia** + This should become event-sensitive. Suggested multiplier: + ```text + officia_cost = base_officia * status_multiplier * event_pressure + ``` + Where `status_multiplier` rises with `auctoritas` and `clientela`. + +4. **Pottery transport** + The local cup is useful as a production baseline but not as a lucrative trade good. Transported ceramics should be modeled in batches, not as single-item cargo. + +5. **Fine ware** + Terra sigillata or stamped fine ware should be a separate product class. It is not merely a plain cup with higher price; it implies different production organization, reputation, and distribution. + +--- + +## 10. Bibliography and Evidence Notes + +### Primary / ancient evidence + +- **Diocletian, Edictum de Pretiis Rerum Venalium**, AD 301. Used only as a later Roman relative price and wage schedule, not as direct 14 BCE pricing. +- **Polybius, Histories**, Book 6. Used for Republican military pay/ration context. +- **Suetonius / Augustus-era military-pay tradition.** Used indirectly through modern synthesis for Augustan stipendium. + +### Modern works and datasets consulted + +- Antony Kropff, *An English translation of the Edict on Maximum Prices, also known as the Price Edict of Diocletian*, version 2.1, 2016. + URL: https://kark.uib.no/antikk/dias/priceedict.pdf + +- Walter Scheidel, *Real wages in Roman Egypt: A contribution to recent work on pre-modern living standards*, Princeton/Stanford Working Papers in Classics, 2008. + URL: https://www.ancientportsantiques.com/wp-content/uploads/Documents/AUTHORS/Scheidel2008-Wages.pdf + +- J. Theodore Peña, *Roman Pottery in the Archaeological Record*, Cambridge University Press, 2007. + Used for pottery lifecycle framing: manufacture, distribution, use, reuse, maintenance, recycling, discard, reclamation. + +- Heli Kiiskinen, *Production and Trade of Etrurian Terra Sigillata Pottery in Roman Etruria and beyond between c. 50 BCE and c. 150 CE*, 2013. + Used for transport/distribution relevance of Italian terra sigillata and the caution that pottery trade involved multiple models. + +- Richard Duncan-Jones, *The Economy of the Roman Empire: Quantitative Studies*, 2nd ed., Cambridge University Press, 1982. + General calibration background for prices, costs, and quantitative Roman-economy evidence. + +- Peter Temin, *The Roman Market Economy*, Princeton University Press, 2013. + General market-context support. + +- Walter Scheidel, Ian Morris, and Richard Saller, eds., *The Cambridge Economic History of the Greco-Roman World*, Cambridge University Press, 2007. + General economic background and scale calibration. + +- Jean Andreau, *Banking and Business in the Roman World*, Cambridge University Press, 1999. + Used for commercial-network context. + +- Koenraad Verboven, *The Economy of Friends: Economic Aspects of Amicitia and Patronage in the Late Republic*, Latomus, 2002. + Used for `officia`, patronage, and social-economic obligations. + +- Philip A. Harland, *Associations, Synagogues, and Congregations*, 2nd ed., 2013. + Used for collegial and association behavior as social-economic context. + +--- + +## 11. Implementation Note + +Recommended database insertion pattern: + +```text +parameter_drift_log.trigger_type = 'otium_access_fee' +parameter_drift_log.delta_note = 'Commercial information access and factor network maintenance.' +parameter_drift_log.value_after = liquiditas_before - OTIUM_ACCESS_FEE_DN + +parameter_drift_log.trigger_type = 'personal_maintenance' +parameter_drift_log.delta_note = 'Food, lodging, clothing upkeep, light, and local movement.' +parameter_drift_log.value_after = liquiditas_after_access - PERSONAL_MAINTENANCE_DN + +parameter_drift_log.trigger_type = 'officia_obligation' +parameter_drift_log.delta_note = 'Patronage, tips, gifts, collegial contributions, and unrecovered favors.' +parameter_drift_log.value_after = liquiditas_after_maintenance - OFFICIA_OBLIGATION_DN +``` + +This preserves the current `−8 dn` design while making the ledger explainable and citable.