Network Analysis to understand the Roman Commerce

Pau de Soto

Roman Empire

COHESION

Network Analysis to understand the Roman Commerce

Territory covering all the Mediterranean, from Northern Western Europe to Near and Middle East.

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Created

Maintained

NETWORKS

Roman Empire

COHESION

Network Analysis to understand the Roman Commerce

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Created

Maintained

NETWORKS

All levels of Roman life

HousesClient

System

CitiesPolitic

System

Roman Empire

Network Analysis to understand the Roman Commerce

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NETWORKS

All levels of Roman life

HousesClient

System

CitiesPolitic

System

Empire - Communication Systems

complex transport infrastructures

put together a lot of communities

Political, economical & social movement

The Commerce of the Roman Empire

Network Analysis to understand the Roman Commerce

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The Project Objectives:

1) An approach to the Roman Transport Network Morphology

2) Reconstruction of the Roman Transportation Systems

• Which infrastructures did they build? • How the Romans transformed their territories?• Does the connectivity of their cities reflect their

political, social or economical interests?

• Can we reply the Roman Transport Movements?• Can we know the costs and times needed to move Roman goods?

Network Analysis to understand the Roman Commerce

1. NE of Iberian P.

2. Hispania3. Britannia4. Italy

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The Project Evolution:

To study all these networks it is mandatory to know how were the Roman Transport System.

Network Analysis to understand the Roman Commerce

Divided into:• Sea

Communications• Inland Waterways • Land Transport

The Roman Transport System

Network Analysis to understand the Roman Commerce

Two wide spaces:

• Mare Nostrum• Atlanticum Mare (Mare Externum/

Oceanus)

Maximum support to the economy of RomeSea Transport

• Most widespread• The fastest

system• Highest

capacities • The Cheapest• Meteorology• Closed on winter• Dangers

(Pirates)Rome understood the importance of the maritime navigation, specially in medium - long travels.

Network Analysis to understand the Roman Commerce

Transport system with big duality:

DownstreamUpstream

Best way to penetrate in inland territoriesRiver Transport

• Fast way (downstream)

• Good capacities • Cheap

• Needs energy (upstreams)

• Slow (upstreams)

• Depends on Geography

Limitations:• Geography• Climatology (specially on the

Mediterranean)• Need of building infrastructures

(leeves)

Lots of Roman cities with river connections:• Rome• Londinium• Caesaraugusta• Hispalis

Network Analysis to understand the Roman Commerce

Only system that connect everyplace of the EmpireLand Transport

• Higher Security• Access to all

Empire• Lower capacity• Slower • More Expensive

Rome built more than 300.000 kms of land routes.

• These huge road network is used to define Rome as a truly empire.

• The land transports was the only way to connect all the cities and territories of the Roman Empire.

• Those roads were used for military, politic, economical and propaganda functions.

Network Analysis to understand the Roman Commerce

The motivations for the construction of the transport network changed over the time.

• Support of armies and colonies.

Networks should cover all needs

Ove

r Tim

e

• Economic and Political needs.

• Social and Religious motivations.

The Roman Transport System

How to study the territorial configuration?How to analyse the commerce?How explain the movement of Roman goods?

How get close to the mobility of the Romans?

We know the infrastructures and the transportation systems…

Digital Recording

Quantifying the Roman Transport System

GIS

Dig

italiz

ing

Network Analysis to understand the Roman Commerce

Network Analysis

Transform the reality in nodes (points) and edges (lines)

Transform cities into nodes (points) and routes into edges (lines)

Origin: Graphs Theory by L. Eulen (1736)Koningsberg

VALUES Calculations

Social Network Analysis

- Accessibility

- Cost & Time Transport

Methodology: Use all available data to obtain the most accurate reconstruction of the Roman Roads, navigable rivers and sea connections:

Quantifying the Roman Transport SystemDigitalizing

Archaeological data:– Mansiones.– Milestones.– Stretches of roads.– Villae and rural settlements.– Necropoli, Roman cemeteries– Bridges, …

Geographic Reality:− Mountains− River steps

Historical & Ethnographical Data:− Medieval - XIXth Cent.

Network Analysis to understand the Roman Commerce

Result: High detailed transport network.

Network Analysis to understand the Roman Commerce

Acessibility

Main concept:

Cities with higher connectivity

More important settlements=

Connectivity

Political, economic and social significance

Degree Centrality:

Betweenness Centrality:

Closeness Centrality:

Network Analysis to understand the Roman Commerce

Calculating the Accessibility

Accessibility = Centrality:More intuitive, simple

More connections = More important

Network Analysis to understand the Roman Commerce

Calculating the Accessibility

Origin in Social Network Analysis

# edge = # value

2. According to the means of transport

Sea Transport 1

River Transport 2

Land (Main Road) 3

Land (Secondary R.) 4

1. Classic (Sociology)

New method of calculation

1 sea 3,4 river (downstream) 6,8 river (upstream) 43,4 land (wagon) 50,7 land (donkey)

Value of edges depending on the type of transport

Network Analysis to understand the Roman Commerce

Calculating the Accessibility

Network Analysis to understand the Roman Commerce

The accessibility results shows us the network configuration in each territory in a specific historical moment.

Accessibility

Diff

eren

t pe

riods

Roman Times (s. II AD)

XVIth Century

Higher values (red/yellow) show territories

well connectedImportant cities and territories

Network Analysis to understand the Roman Commerce

Accessibility - Hispania

Transport infrastructures were developed following the geography, natural resources (mines) and military settlements.

Rome was interested in fully exploit the coast areas and the closer locations in the river valleys.

Network Analysis to understand the Roman Commerce

Accessibility - Italy

Rome built her land routes thinking in a political and military connections

Rome was perfectly connected with the rest of the Empire

Network Analysis to understand the Roman Commerce

Accessibility - Britannia

Armies in Britannia

Optimize the metropolis-colony connections.

London was the centre of the transport network.

HOW? Implement of constant values per kilometre

Cost & Time

✓ the shortest.✓ the most economical.✓ the faster.

Best Route

Network Analysis to understand the Roman Commerce

Once we know the length of each trip we can use constant values.Methodology to import values.

Introducing cost & time values

Cost of travel:− The length of the trip− The Costs of transports:

− The characteristics of vehicles− The load capacities− Roman prices

Time of travel:− The length of the trip− The speed of vehicles

T(time) = L(length) / Sv (speed value)

C(cost) = L(length) * Cv (cost value)

Mule driver, camel driver with maintenance......................25 modiiWater carrier working a full day with maintenance............25 modii

Network Analysis to understand the Roman Commerce

Based on classical sources and archaeology:

Values

1 sea 3,4 river (downstream) 6,8 river (upstream) 43,4 land (wagon) 50,7 land (donkey)

Network Analysis to understand the Roman Commerce

The values of speeds and costs are entered into the GIS as constant values for each kilometre in route.

Introducing the Values

new tables

1Each section has its own cost & time

Network Analysis to understand the Roman Commerce

Finally we can calculate the transport costs & times from one point to the rest of the network

Closer view to the mobility of the transport systems.

Time

Ancient sources = temporal patterns / not distances

The travels were counted in days and not in numbers of miles travelled.

“Go, my little book, go; accompany my Flaccus across the wide, but propitious, waters of the deep, and with unobstructed course, and favouring winds, reach the towers of Hispanian Tarragona. Thence a chariot will take you, and, carried swiftly along, you will see the lofty Bilbilis, and your dear Salo at the fifth stage…”

Knowing the time needed to travel is a important information to understand the distribution of certain products, especially those of low durability.

Network Analysis to understand the Roman Commerce

Time

Network Analysis to understand the Roman Commerce

Time

Network Analysis to understand the Roman Commerce

It is the analysis of the movement of goods from its transportation cost.

Costs

The goods were moved until their price was prohibitive for commercialization

Observe cost patterns and influential areas of

distribution

Network Analysis to understand the Roman Commerce

Objective: Not replicate one single travel cost

Network Analysis to understand the Roman Commerce

Costs

Firsts analysis in NE - Hispanic

Accessibility - Hispania

The territories more accessible were always near the coast or in areas with river connections.

Inside peninsula was heavily insulated. This fits with the archaeological data that is documented in inland sites.

Network Analysis to understand the Roman Commerce

Network Analysis to understand the Roman Commerce

Accessibility - Italy

From Arezzo, the natural way to export was the Tyrrhenian Sea coast.

Many coastal territories were easily accessible. There were important commercial ports

Network Analysis to understand the Roman Commerce

Accessibility - Britannia

Except for points near the coast, many of hinterland were isolated. This situation is especially prominent in the northern territories.

London represented a good redistribution point of goods both export and import

Network Analysis to understand the Roman Commerce

The Roman Empire was based on a highly organised economical and political communication network.

Initially, the routes especially by land, were designed according to military and political criteria to link territories related to Rome.

The organisation of territories was made taking into account the advantages of geography, building cities along the coast and in easily accessible river valleys.

The model of communication in Italy was very different from Hispania and Britannia.

The Italian model was configured in a long time, and did not respond especially to an economical criteria.

Hispania and Britannia were seen as models of land exploitation.

Conclusions

The Roman Empire

Network Analysis to understand the Roman Commerce

The study of the Roman transport network is very necessary to understand the roman economy and history.

The transportation network in Roman Times was indispensable to keep together the territories with such heterogeneous cultural background.

The political integration required integration in terms of economy and communication.

The transport network was a key factor in the success of the Roman Empire.

Conclusions

The Roman Empire

Network Analysis to understand the Roman Commerce

It is an unfinished project.

But it can shows some interesting results.

It provides new data to the study of economics and history of Rome.

The Network Analysis provides us new information on past transport conditions to better understand past economies.

A more complete study of the whole network, province by province, is required to understand all the Roman transport system.

GIS is an exceptional tool for modelling transport and accessibility

Conclusions

Project

Wider territories

More detailedNetwork Analysis to understand the Roman Commerce