Common perception of medieval food and cooking is still largely influenced by books, journals, movie and TV series. All people were knights and no one was interested in table manners and vegetables. Rosted meat - gnawed right off the bone - was the main part of each feast. The farmers were poor and had to work hard for their frugal food. The aristocracy and the church took what ever they could from farmers and labourers. So the food of "the common man" was frugal and mostly vegetarian. At least that is the image many people still have and which historic sources like Johannes Boemus seem to support.
Therefore it is not surprising that within the vast number of "medieval cookbooks" many don't use historic medieval sources as base for their recipes. The most historic times they refer to are the 19th and early 20th centuries and the "traditional" cuisine of our grand parents and original ancestors. But still they sell their cooking as "original medieval".
If we look at all available sources, it shows that the "Middle Ages" never existed as a uniform epoch. We talk about a time span of ca. 1000 years (from ca. 500- ca. 1500) with many turning points and developements. The common division into early middle ages (500-1000), high middle ages (1000-1250) and late middle ages (1250-1500) is a conception of the 19th century. Scholars tried to give a better picture of the time by dividing it using historical events. Many sectors of dayly living - including food and cuisine - can't be correlated with these dates and the transitions mostly are blurred.
In the following parts of this series I want do give a vage view into the developement of medieval diet and cuisine in particular of the German language area starting in the early middle ages. My main focus will be on late medieval cooking because of the big number of still existing written sources.