otivm/docs/cities/CITY-OSTIA-0001.md

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

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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.

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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

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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.

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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.

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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.

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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

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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

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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.

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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

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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

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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

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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

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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.

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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

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14. Relations

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 ↑

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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

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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

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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.