# CITY-OSTIA-0001
## Ostia Substrate — Origin City for OTIVM
### Status: Canonical City Seed
### Layer: OTIVM (Roman Merchant)
### Purpose: Establish the simulation substrate for Ostia as origin city, social field, logistics node, and scenario environment
### Repository Path: docs/cities/CITY-OSTIA-0001.md

---

## 0. Design Intent

This document defines Ostia as a working simulation environment.

It is not a tourist description and not player-facing prose. It exists to give scenarios, actors, costs, routes, and social encounters a grounded urban substrate.

Ostia must support:

- the MERCATOR's starting condition
- the six starting backgrounds
- SCENARIO-MERCHANT-0000, the prologue conversation
- SCENARIO-MERCHANT-0001, the bronze forge fire
- Route I, Ostia -> Capua
- future finance, storage, labor, and reputation mechanics

Ostia is the first city the participant must learn to read.

---

## 1. Canonical Identifier

| Field | Value |
|---|---|
| City ID | `CITY-OSTIA-0001` |
| City Token | `ostia` |
| Roman Name | OSTIA |
| Modern Location | Ostia Antica, Lazio, Italy |
| Role | origin city / port / grain and cargo interface |
| Default Epoch | `roman_14bce` |
| Primary Route | Ostia -> Capua |
| Repository Path | `docs/cities/CITY-OSTIA-0001.md` |

---

## 2. Chronological Scope

Default scenario epoch is approximately 14 BCE.

This matters because many of the most visible excavated features of Ostia belong to later Imperial development, especially the Trajanic and Hadrianic phases. The city substrate must therefore distinguish:

| Feature | 14 BCE Use |
|---|---|
| Republican colony and port function | admissible |
| Tiber mouth logistics | admissible |
| Via Ostiensis connection to Rome | admissible |
| early warehouses / storage | admissible, but scale uncertain |
| dense later Imperial warehouse landscape | later analogue only |
| major later bath complexes | later analogue unless dated earlier |
| Claudian / Trajanic Portus system | not yet built |
| 2nd c. CE peak population estimates | upper-bound analogue, not 14 BCE fact |

Rule: use later Ostian archaeology as structural analogy only when explicitly tagged.

---

## 3. Historical Basis

Ostia was Rome's river-mouth port and a key interface for grain, salt, military, and commercial movement. It stood at the Tiber mouth, connected to Rome by river traffic and the Via Ostiensis.

Evidence basis:

- mid-to-late Republican Ostia became important to Rome's food-supply system
- first warehouses at Ostia are dated to the 1st century BCE
- city walls were constructed between 63 and 58 BCE and enclosed roughly 70 ha
- major Imperial horrea are better documented for the 1st and 2nd centuries CE
- later peak population estimates cluster around tens of thousands, commonly 36,000 to 60,000 for the 2nd century CE
- baths in Ostia were major social infrastructure in later visible archaeology

Confidence: Medium for general urban role.  
Confidence: Low to Medium for quantitative 14 BCE population and prices.

---

## 4. Population Model

Population must be treated as a range, not a fixed number.

Later Imperial peak estimates cannot be directly applied to 14 BCE. For simulation purposes, use population bands.

| Population Component | 14 BCE Working Range | Confidence | Notes |
|---|---:|---|---|
| permanent residents | 8,000–20,000 | Low | inferred from urban area and pre-Imperial development |
| enslaved population | 20–40% of resident population | Low | varies by household, warehouse, workshop |
| transient sailors / haulers / traders | 500–5,000 seasonal | Low | tied to shipping season and cargo cycles |
| warehouse and dock labor | 500–2,500 | Low | depends on port traffic intensity |
| officials / clerks / customs personnel | 50–300 | Low | tied to annona, tax, port administration |
| elite / municipal families | small minority | Low | influence exceeds numbers |

Simulation rule: population is not a static backdrop. Seasonal traffic should alter lodging demand, food prices, labor availability, theft risk, disease risk, and rumor velocity.

---

## 5. Urban Zones

### 5.1 Riverfront / Port Interface

Primary functions:

- landing and unloading
- cargo inspection
- short-haul transfer
- porterage
- storage assignment
- gossip and price discovery

Likely actors:

- sailors
- porters
- warehouse workers
- customs personnel
- agents
- muleteers
- small merchants
- freedmen managing cargo

Simulation uses:

- cargo arrival events
- rumor propagation
- theft risk
- PORTORIUM / fee exposure
- labor hiring
- first signal of distant shortages

### 5.2 HORREA / Storage District

Primary functions:

- grain storage
- oil / wine storage where appropriate
- privately owned storage
- imperial or public storage analogues
- protected goods
- collateralized inventory

Important distinction:

Large, well-preserved horrea are mostly Imperial and later than 14 BCE, but the presence of 1st c. BCE warehouses supports a storage substrate in the default epoch.

Simulation uses:

- storage cost
- spoilage risk
- credit collateral
- theft risk
- market delay
- warehouse fire scenarios
- disputes over goods held or pledged

### 5.3 Market Streets and TABERNAE

Primary functions:

- small retail
- food sales
- repair
- money exchange
- daily hiring
- information exchange

Simulation uses:

- food price index
- lodging rumors
- worker availability
- small-goods purchase
- background-specific contacts

### 5.4 Workshop Districts

Primary functions:

- metalwork
- carpentry
- leather repair
- cart and harness repair
- amphora handling / repair
- small production

SCENARIO-MERCHANT-0001 uses an industrial / mixed-use workshop zone with inherited land value, water access, and transport frontage.

Simulation uses:

- workshop output
- tool price index
- displaced labor
- fire risk
- repair queue
- district access penalty

### 5.5 BALNEA / Baths

Primary functions:

- bathing
- gossip
- cross-status observation
- political talk
- hiring and introductions
- reputation performance

Baths are the preferred setting for SCENARIO-MERCHANT-0000 because they plausibly allow mixed-status contact between backgrounds that would not share domestic dining space.

Simulation uses:

- background choice prologue
- rumor comparison
- AVCTORITAS performance
- CLIENTELA discovery
- class-coded interaction

### 5.6 Inns, Cauponae, Thermopolia

Primary functions:

- meals
- cheap lodging
- storage of gossip
- transient-worker congregation
- low-status deal making

Simulation uses:

- lodging cost
- food cost
- rumor source
- theft risk
- freedman and camp-logistician contacts

Terminology note: THERMOPOLIVM is plausible for a prepared-food shop, but the prologue should prefer BALNEA / baths if all six backgrounds must plausibly share one scene.

### 5.7 Administrative / Legal Nodes

Primary functions:

- contracts
- witnessed transactions
- petitions
- local magistrate contact
- dispute handling
- tax enforcement

Simulation uses:

- legal enforceability
- witness strength
- ius_accessus modifiers
- creditor pressure
- collateral recovery

### 5.8 Residential Layers

The actor backgrounds require different residential anchors.

| Background | Likely Starting Residence | Notes |
|---|---|---|
| Former Legionary | modest room near gate / transport zone | values direct access and low cost |
| Freedman Trader | taberna back room or rented upper room | close to market signals |
| Noble Younger Son | dependent lodging with patron / better insula apartment | status exceeds liquiditas |
| Failed Magistrate | respectable but debt-burdened lodging | social appearance matters |
| Camp Logistician | cheap lodging near haulers / stables | practical, mobile |
| Guild Scribe | room near collegium or records office | access to accounts and gossip |

---

## 6. Infrastructure Parameters

| Parameter Token | Type | Confidence | Notes |
|---|---|---|---|
| river_access | location | High | core to Ostia's function |
| via_ostiensis_access | movement | High | route to Rome |
| warehouse_capacity | resource | Medium | exact 14 BCE scale uncertain |
| dock_congestion | movement | Medium | derived from cargo season |
| porter_availability | labor | Medium | seasonal and event-sensitive |
| bath_access | social | Medium | strong later evidence, earlier scale uncertain |
| fire_risk_urban | event | Medium | dense mixed-use settlement |
| disease_risk_seasonal | health | Low | plausible but needs source development |
| rent_pressure | market | Low | inferred from transient population |
| rumor_velocity | information | Medium | port-city logic |

---

## 7. Cost and Price Bands

These are placeholders for research refinement. They must not be treated as final database values.

| Cost Item | Working Value | Unit | Confidence | Notes |
|---|---:|---|---|---|
| cheap meal | 0.25–1.0 | as / meal | Low | broad Roman analogue |
| modest meal | 1–4 | asses / meal | Low | urban analogue |
| bath entry | 0.25–1.0 | as | Low | needs source confirmation by period |
| cheap lodging | 1–4 | asses / night | Low | inferred from urban lodging |
| porter day wage | 1–4 | asses / day | Low | requires primary source calibration |
| skilled artisan wage | 4–16 | asses / day | Low | broad analogue |
| mule hire | TBD | denarii / day | Low | requires route research |
| cart hire | TBD | denarii / day | Low | requires route research |
| warehouse storage | TBD | per unit / day | Low | must be researched |
| scribe / witness fee | TBD | per contract | Low | needed for FAENVS scenario |

Rule: low-confidence economic values are still retained because they identify where uncertainty lives.

---

## 8. Social Nodes

| Node | What It Produces | Backgrounds Favored |
|---|---|---|
| BALNEA | mixed-status rumor, public reading of character | all |
| HORREA | cargo intelligence, theft risk, collateral opportunities | freedman trader, guild scribe |
| Riverfront | arrival news, porter labor, route signals | legionary, camp logistician |
| Collegium House | contracts, obligations, mutual aid | guild scribe, freedman trader |
| Tavern / Thermopolium | low-status gossip, labor news | freedman trader, camp logistician |
| Legal Forum / Magistrate Contact | enforceability, creditor pressure | noble younger son, failed magistrate |
| Stables / Grazing Yard | animal hire, cart availability | legionary, camp logistician |

---

## 9. Scenario Dependencies

### SCENARIO-MERCHANT-0000 — Baths Prologue

Ostia must support a mixed-status conversation where all six backgrounds plausibly interpret the same rumor differently.

Recommended setting:

- BALNEA, not private dinner
- near enough to smoke, rumor, or port news
- public enough that status is performed
- informal enough that low-status actors can speak

### SCENARIO-MERCHANT-0001 — Bronze Forge Fire

Requires:

- mixed-use workshop district
- valuable old plot
- water or road frontage
- adjacent worker / animal / transport activity
- rumor network
- creditor visibility
- municipal weakness or ambiguity

### SCENARIO-MERCHANT-0002 — Capuan Timber Yard Fire

Ostia dependency:

- outbound cargo purchase
- news delay from Capua
- goods available before Capua reprices
- hauler / cart availability

### SCENARIO-MERCHANT-0003 — FAENVS Offer

Ostia dependency:

- ability to identify distressed counterparties
- witnesses
- legal pressure
- reputation effect
- capital lockup competing with cargo venture

---

## 10. Background Interaction Matrix

| Background | What Ostia Shows Them First | Blind Spot |
|---|---|---|
| Former Legionary | routes, discipline failures, transport bottlenecks | hidden finance |
| Freedman Trader | mispriced goods and ignored markets | elite legal risk |
| Noble Younger Son | social hierarchy and access points | operating costs |
| Failed Magistrate | leverage, signatures, favors owed | public distrust |
| Camp Logistician | supply movement and shortage timing | prestige etiquette |
| Guild Scribe | debts, records, counterparties | physical danger |

---

## 11. Daily Rhythm Model

| Time | City State | Simulation Use |
|---|---|---|
| dawn | porters, animal handlers, bakers, smoke reports | early labor and event signals |
| morning | market setup, legal errands, loading | contract and cargo actions |
| midday | heat, baths begin filling, gossip consolidates | social encounters |
| afternoon | price negotiation, dispatch decisions | venture commitment |
| evening | taverns, account reckoning, rumors mutate | risk and information events |
| night | theft, fires, covert meetings | hidden events |

---

## 12. Seasonal Rhythm Model

| Season | Expected Effects |
|---|---|
| winter | maritime risk, slower movement, disease and damp risk |
| spring | increased movement, river reliability, labor demand |
| summer | heat, spoilage, lower Tiber concerns, crowding |
| autumn | renewed movement, price adjustment, storage pressure |

Need further research: relationship between MARE CLAVSVM, river levels, and local Ostia storage demand.

---

## 13. Parameter Candidates

| Parameter Token | Domain |
|---|---|
| ostia_population_band | demographic |
| transient_population_factor | demographic |
| dock_congestion_index | movement |
| warehouse_capacity_index | resource |
| porter_availability | labor |
| cart_availability | movement |
| bath_social_density | social |
| rumor_velocity | information |
| legal_access_index | institutional |
| fire_risk_index | event |
| rent_pressure_index | market |
| food_price_index | market |
| storage_fee_index | cost |
| theft_risk_index | security |
| disease_risk_index | health |
| creditor_visibility | finance |
| collegium_presence | social |
| portorium_exposure | cost |

---

## 14. Relations

```text
transient_population_factor ↑ -> rent_pressure_index ↑
transient_population_factor ↑ -> rumor_velocity ↑
dock_congestion_index ↑ -> porter_wage ↑
dock_congestion_index ↑ -> cargo_delay ↑
warehouse_capacity_index ↓ -> storage_fee_index ↑
storage_fee_index ↑ -> distressed_sale_probability ↑
bath_social_density ↑ -> rumor_velocity ↑
fire_risk_index ↑ -> workshop_output_volatility ↑
legal_access_index ↑ -> contract_enforceability ↑
clientela ↑ -> information_quality ↑
auctoritas ↑ -> witness_reliability ↑
food_price_index ↑ -> labor_unrest_risk ↑
cart_availability ↓ -> venture_cost ↑
```

---

## 15. Evidence and Source Notes

Primary source targets for future refinement:

- Cicero, letters and speeches for social/legal/commercial norms
- Livy for early Ostian military and civic references
- Pliny the Younger, Epistulae 5.6.12 for Tiber seasonality analogy
- Digest of Justinian for contract and enforcement categories
- Diocletian's Price Edict for later comparative price structure only

Archaeological / scholarship targets:

- Russell Meiggs, *Roman Ostia*
- Geoffrey Rickman, *Roman Granaries and Store Buildings*
- Carlo Pavolini, *La vita quotidiana a Ostia*
- Gustav Hermansen, *Ostia: Aspects of Roman City Life*
- Ostia-Antica.org topographical dictionary
- geoarchaeological studies of the Roman port-city of Ostia

Current verified basis from preliminary research:

- 1st c. BCE warehouses existed at Ostia
- Republican walls enclosed roughly 70 ha
- Imperial population estimates are much later and must be used only as upper-bound analogues
- horrea were concentrated near the Tiber and did not serve Ostia alone
- baths were social infrastructure used across status boundaries in the Roman world, with strong evidence at Ostia in later archaeology

---

## 16. Repository Use

Internal simulation substrate. Not player-facing text.

Use this document to support:

- scenario placement
- prologue construction
- background starting conditions
- cost registry development
- urban parameter registry
- Route I preparation
- future city comparison documents

---

## 17. Canonical Success Condition

If Ostia stops functioning as a painted backdrop and starts functioning as a pressure field — where rents, rumors, labor, storage, status, and routes push on every MERCATOR differently — then this document is functioning correctly.