Finding solid information on medieval logistics was challenging. Some good books or articles have been published. But you need to piece together a lot of knowledge from brief references.

Books like Gregory Bell’s Logistics of the First Crusade: Acquiring Supplies Amid Chaos, Donald Engels’s Alexander the Great and the Logistics of the Macedonian Army, and Martin Van Creveld’s Supplying War: Logistics from Wallenstein to Patton were useful for basic details like the weight of a daily ration or the ratio of wagons to men in an army’s supply train.

Academic journal articles provided a lot of the specifics I was looking for. I benefited from having access to college and university libraries and databases when I was seeking articles like Frederic Lane’s “Tonnages, Medieval and Modern,” from The Economic History Review.

After doing this research, I can make some quick calculations that I found to be helpful for maintaining some level of realism. If you want to move 4,500 horses across a sea, for example, you need at least 150 horse transport ships to make the transfer in one trip.

One mule, for example, could carry about five eight-person tents (at ~forty lbs. each) or ~one day of rations (food/drink) for ~25 soldiers or ~ one day of oats/grain for ~11 horses or mules.

A normal cog, with a crew of ten to eighteen sailors, could carry about 50 to 100 wagon/cart loads of cargo. (up to 200 loads). Ships that could carry more than 100 or 200 loads existed but they were rare and highly valued. A river barge could carry ~20 loads, or 20 tons.

I’ll need a while to finish my work, but eventually I’ll publish more summary facts and statistics in the website’s Compendium section.

Addendum: Gregory D. Bell’s Logistics of the First Crusade: Acquiring Supplies amid Chaos (2019) is my most recent reading in this area. I appreciate Bell’s argument that the leaders of the crusading contingents weren’t as clueless about logistics as some stereotypes lead you to believe (because the stereotypes are repeated without careful confirmation in many general histories).

Addendum: Roger Crowley’s City of Fortune: How Venice Ruled the Seas has an interesting section about the Treaty of Venice (~1201 A.D.), the agreement to transport and supply the Fourth Crusade. The Venetians calculated the provisions for one man for one year: 377 kilos of bread and flour, 2,000 kilos of cereals and beans, and 300 liters of wine (36).

Note: One common question concerns the nature of the rations armies carried or hauled with them as they went on campaign. Barbara Tuchman, in A Distant Mirror: The Calamitous 14th Century offers a list of campaign foods: wheat biscuit, salt pork, bacon, hams, smoked fish (mackerel, salmon, and eels), dried herring, dried peas and beans, onions, cheeses, rice, barley, almonds, olive oil, salt, sugar, wine, beef cattle, sheep, capons, hens, geese, ginger, pepper, saffron, cinnamon, and cloves” (446). Presumably the army would purchase or forage for grain and ale on the march. Tuchman’s book, by the way, is a great starting point if you are interested in learning more about the medieval period. She uses an engrossing method of telling a story from the perspective of one person’s life.