Let’s return again to the medieval food supply.

Modern people often underestimate how large of an issue securing an adequate amount of food calories was for most medieval people. Even in modern times, especially during periods of widespread wars, revolutions, or natural disasters, the issue frequently elevates to top of mind for many humans. Read Lizzie Collingham’s The Taste of War: World War II and the Battle for Food (2011) for one reminder of how precarious food supply chains are. After reading that book, I promise that you will see wars, and military history in its entirety, from a different perspective.

For food production, we’re technically talking about gathering, hunting, poaching, fishing, farming, and animal husbandry. These activities are complex domains of human knowledge and experience, so I have several pieces of advice for medievalist writers who also want to remain sane.

First, pick a small entry point into your study—for example, the growing of grain or the operations on a typical family farm. Even a narrow subject can consume years of study. And while you can pursue the inquiry for as long and as deeply as your curiosity lasts and takes you, your probable purpose is finding some useful specifics for verisimilitude or gauging the plausibility of something you want to happen. Keep a manageable focus.

Second, make your peace with imprecision and uncertainty. If you do not, medieval treatments of numbers, quantities, and weights will soon having you pulling out fistfuls of your hair or banging your head against your desk over and over again.

Finally, seek an understanding of the general patterns relevant to the activity you are examining and their impacts on other aspects of human activity. For example, looking at farming, the windows for sowing crops and harvesting them are relatively fixed and inflexible, and most human communities that want to survive through the next winter felt incredibly strong incentives to focus primarily on those tasks during certain months of each year. Missing the windows always, always had devastating consequences.

Farming, for example, followed a predictable cycle of time that affected when organized military campaigns occurred. Many books contain an overview of the planting and harvesting cycles. Daily Life in Chaucer’s England, which I recommended in my last post, offers one of the clearest summaries I’ve seen so far. But basically arable land needed its plowing to start in February so that the planting of barley, oats, peas, vetches, and beans could finish by the end of March. Then, the farmers harvested hay from the meadows in July and grain through August and into September so that they could plow for winter crops (wheat, rye) in October and plant before November 1 or, at the latest, November 11.

So in any society relying on a medieval muster and located in a temperate zone, the wide window for fighting ran from March through October and the narrow window, ideally between April and June. In years after a bad harvest, stores of cereals and other produce would start to run low by the middle of the year (i.e., well before the next harvest), and difficult tradeoffs regarding slaughtering livestock might start much early than the usual November culling.

A virgate of arable land, the amount necessary to support one nuclear family and produce some surpluses, or roughly forty acres of arable, would need somewhere around thirteen and twenty acres of plowing for the crops and, ideally, plowing of the fallow fields to aid in the soil replenishment each year. At different times, a two-field or three-field rotation system was operating on most manors. A portion of the land sat fallow each year to replenish the soil so that yield stayed at regular levels.

But the margins often were tight for many families. According to some of my sources, as I summarized in this earlier post, each person needed the produce from about 2.5 acres to survive the year. A family could survive off a half-virgate with little or no surplus, but many families held less land than a half-virgate. Those families needed to earn enough in supplemental income to buy somebody else’s surpluses.

Yields for crops varied, ranging in best cases from about 1:7 to 1:15, but most sources indicate an average ratio of about one to 4.5 or five. Each bushel of seed planted yielded roughly those number of bushels of crops. Then, seed stock for the next year needed to be set aside. The remainder was available for consumption or trade.

Given these realities and the realities of increased consumption of soldiers in active training or fighting, you can understand why feudal service obligations typically lasted for only forty days per year. You can see why raids in force, or basically quick looting expeditions (the French term was a chevauchée), were more popular than sieges. Eventually the wealthier kingdoms that generated regular surpluses shifted to a standing professionalized army, in part, to lengthen the campaigning season. Having an eight- or nine-month campaign season as well as reliable winter garrisons opened a lot of strategic possibilities for commanders.