Combien de temps pour un Paris/Marseille dans l’Empire Romain ?

Channel's first live episode on Twitch, condensed into a YouTube video to analyze travel in the Roman Empire.

How long did it take to travel from one point to another in the Roman Empire, particularly for the Paris-Marseille route in ancient times.

Orbis, a tool developed by Stanford University in 2012 functioning like a Google Maps simulation of the Roman Empire.

Exploring how the Orbis model works and its limitations while traveling virtually through the Roman Empire.

Roman roads developed over approximately six to seven centuries, with the first major road, the Via Appia, built in the 3rd century BCE, connecting Rome to Capua and later extended to Brindisi.

• Roads were built primarily for strategic and political reasons. • Enable rapid military intervention if problems arose in the empire. • Roads are characterized by very straight routing to shorten distances.

At its peak, the road network extended to approximately 85,000 kilometers of cumulative roads, developed mainly during the first two centuries CE under the Pax Romana established by Augustus.

The Roman Empire at its height spanned three continents, representing approximately one quarter of humanity, requiring considerable logistics to be administered.

No regular maritime lines connecting ports. Coastal trading, or hugging the coast, was the primary maritime transport mode for goods and people.

• Ships were very expensive to build. • Sea voyages were dangerous and exposed to attacks. • Climatic conditions posed significant risks. • Only diplomats and the wealthy could afford these voyages.

High-sea voyages existed but remained exceptional, reserved for major diplomatic expeditions or wealthy individuals, and were not the norm for maritime transport.

Maritime routes were added to the Orbis model pragmatically, deduced from several factors, though they do not precisely represent the realities of ancient maritime transport.

• Wars and military movements against barbarians to protect borders. • Official missions carried out by diplomats and ambassadors. • Administrative communication through the cursus publicus, a state postal system.

• Expeditions to discover new coastlines and establish trading posts. • Merchandise commerce by itinerant merchants. • Development of new commercial relationships.

• Tourism restricted to the privileged and wealthy visiting renowned sites. • Travel for health reasons to sanctuaries or thermal stations. • Education of young aristocrats sent to major cities for their training.

Traveling troupes, skilled artisans, bankers, and renowned physicians traversing roads to offer their services.

• The cheapest but slowest mode. • Used notably by soldiers conducting experimental marches. • Legion 8 Augusta conducted marches with full equipment over 120 kilometers.

• Two or four-wheeled carts carrying up to half a ton of cargo. • Simple basic carriages or luxurious ones for the wealthy. • Horses for faster travel, donkeys or oxen for the poor.

Paved roads did not permit galloping; parallel dirt roads existed for riders. Renting horses was very expensive. Relay stations existed every 10 to 36 kilometers to change horses or rest.

Travel by boat was possible but extremely costly, required substantial logistics, and exposed travelers to the risk of total loss of cargo.

Latin was not spoken everywhere in the Empire. Language varied by region, creating communication challenges, though signs and gestures allowed minimal understanding.

• Merchants who knew routes and destinations. • Local guides speaking regional languages and knowing roads. • Professional companions to facilitate journeys.

Basic maps on scrolls indicating major cities, exchange places, and mountain passes. These maps were not to scale, had gaps, but provided general orientation.

A system similar to today's Michelin guides, allowing travelers to navigate the complex network of the ancient Roman Empire.

The fastest route from Lutetia (Paris) to Massilia (Marseille) takes approximately 22 to 23 days to cover about 1,080 kilometers, achievable in July according to Orbis.

• A journey requiring substantial preparation and logistics. • Different from modern fast and light journeys. • Requires provisions, equipment, and organization over several weeks.

Travel time varies depending on the transport mode chosen, the season, and many other factors. Oxen cover approximately 2 kilometers per hour, while horses allow about 56 kilometers per day.

Walking journeys average 30 kilometers per day. On horseback approximately 56 kilometers per day. River journeys involve 25 navigable rivers with two types of specialized boats.

• Developed by Stanford University launched in 2012. • Created by Walter Scheidel, historian specializing in economic and social history of antiquity. • In collaboration with Elijah Meeks, data visualization expert working for Netflix and Apple.

• Covers 632 sites including major cities, trade centers, and schools. • 361 maritime ports integrated into the model. • Approximately 84,631 kilometers of cumulative roads. • Approximately 28,272 kilometers of rivers and canals.

The network spans from the 3rd century BCE to the 3rd century CE, compressing six centuries of development into a single map. Some roads were not present at all times, creating potential anachronisms.

A simplified representation covering only major routes. Not all minor roads, rivers, or local maritime routes. Extrapolated maritime routes do not exactly match the historical realities of regular lines.

• Ox cart. • Porter. • Mule cart. • Walking. • Livestock with moderate loads. • Camel caravan. • Fast military march without baggage. • Horse with rider. • Fast private travel. • Express transport. • Horse relay.

On foot: 30 kilometers per day on average. On horseback: 56 kilometers per day. Distances covered vary depending on conditions and the transport mode used.

• Cost in denarii per kilogram of wheat transported. • Paris-Marseille: 14 denarii per kilogram by donkey, 18 denarii by cart. • Passenger transport by cart: up to 1,020 denarii for a full journey. • Different transport modes generating different proportional costs.

Monthly wind conditions, water currents, and wave heights taken into account for maritime journeys. Approximately 1,000 maritime routes modeled with these climate variations.

Orbis uses early 4th century Roman Empire prices, based on Diocletian's Edict (Prices Maximum) setting maximum prices for foodstuffs, raw materials, and wages.

The denarius is the primary currency of the Roman Empire. One denarius equals 16 asses. Diocletian's maximum prices may be biased by the existence of a black market.

• Wheat: 200 denarii per modus (6.5 kilograms). • Barley: 60 denarii per modus. • Oats: 30 denarii per modus. • Beef: 8 denarii per Italian pound (324 grams). • Pork sausages: 12 denarii per ounce (27 grams).

Agricultural laborer: 25 denarii per day, requiring 4 days of work to buy a modus of wheat. Wages varied enormously depending on professions, with significant gaps according to specialized trades.

The model is limited to main routes without covering minor local roads, rivers, or secondary maritime routes. Small-scale movements remain imprecise without additional archaeological data.

• Wind conditions and wave heights are integrated. • Snowfall, sandstorms, and flooding are not modeled. • Effects of extreme heat on travel speed are ignored. • River freezing making navigation impossible is not accounted for.

The model does not account for necessary breaks during travel. Actual travel time is therefore longer than 22-23 days for Paris-Marseille, including nights and rest periods.

The 22-23 day Paris-Marseille journey represents an optimal scenario. Accounting for breaks, variable conditions, and unforeseen circumstances realistically increases travel duration.

Orbis is a remarkable and free tool available on the Internet, allowing simulation of ancient routes and estimation of Roman travel durations and costs.

• Successful fusion of historical expertise and data visualization. • Combination with local archaeological research for better accuracy. • Contributes to understanding Roman economy and logistics.

First live episode on Twitch condensed for YouTube. Format enabling better community interaction and direct exchanges than standard YouTube.

• Intention to repeat this format of live Twitch episodes. • Continued production on YouTube over the summer with surprises. • Possibility of interviews with historians. • Varied gaming content and discussions on channel behind-the-scenes.