The Meister Eberhard manuscript follows its recipe section with a lengthy discussion of the health benefits and risks of various foodstuffs. The text is very conventional, frequently refers to academic authorities, and may well be a copy of a vernacular regimen sanitatis I am yet unaware of (it is not the Tacuinum or Konrad von Eichstätt directly as far as I can tell). I will not reproduce it in full here (though I will put up the entire thing in the finished translation), but I will pick out a few sections of interest. The first one is on lettuce:
<R35> All greens make bad blood, that is melancholy and sadness and bad thoughts and dreams except for lettuce (lattich) and bugloss (ochsen zungenn)
<R36> Lettuce (lattich) chills, and to those who eat it boiled it makes better blood than other greens, and it causes sleep, whether eaten raw or boiled, and is good for people who have been hurt in the head by the sun or who have an inflamed stomach. Those who eat it with vinegar are made hungry and desire food. It is also hot and dries and damages the head, the sight and the stomach and causes many bad dreams. It should be boiled in two waters so that it causes less damage, writes Avicenna.
Lattich, cognate of lettuce, is of course the original German word for the plant that so dominates the salad world of German cookery that we insist on confusing foreigners by calling both the vegetable and the preparation Salat. We do not rightly know how long it has been customary to eat it raw, but by the time of Meister Eberhard, this was clearly a familiar practice. We need to keep in the back of our head that he is not using his own voice here and we cannot be sure to what degree he adapted the advice of writers from classical Antiquity and the Arabic Middle East to his own circumstances, but in this case we have reasonably good evidence. As early as the Carolingian era, monastic reform oders record serving herbas crudas, raw greens, to their brothers. Hildegardis Bingensis, claiming direct divine inspiration, but likely reflecting contemporary practice, wrote in her Physica:
Domestic lettuces (latich) (…) are very cold. Eaten without condiment, their injurious juice makes a person’s brain empty, and they fill his stomach with illness. Whence, one who wishes to eat it should first temper it with dill, vinegar, or garlic, so that these suffuse in it a short timebefore it is eaten. Tempered in this way, lettuce strengthens the brain and furnishes good digestion. (…)
(translation by Prsicilla Throop)
There is some reason to think that this reflects a popular tradition that continues into the sixteenth century and beyond. The salads we encounter in most cookbooks are imported from Italian cuisine, dressed with olive oil and vinegar, but this was likely limited to the tables of the wealthy. When victorious landsknechts at the battle of Marignano in 1515 ate a captured Swiss flag of green silk “…chopped up in a salad” (zerhakt in eim salat), they likely followed a culinary practice they knew. Hieronymus Bock, a noted botanist and physician, write in his Teutsche Speißkammer (1550):
Our peasants, above all in Alsace, abandon vinegar in their salad at harvest time and much rather use onions and garlic, and it also serves them better. … (p. lvii v)
Some wealthy people use olive oil (baumoel) at table with their sauces and salad, more for pleasure than for health. However, poor people use olive oil to treat their illnesses (presten) and find what they need for sale from apothecaries and spice shops (wurtzgaden). Otherwise, the common crowd tends more towards nut oil, poppyseed oil, rapeseed oil (Ruebsamen oeli) and linseed oil than to olive oil. This was caused by the Roman bishop who had the poor naive Germans taught many years ago that (if they wished to be saved), they should and needed to only use nothing but oil for their food during fast times. And because no olive trees grow in German lands, they needed to plant nut trees, poppyseed, rapeseed, hemp and linseed instead so that we would not lack oil both for food and for light in wintertime. (p. lx r)
Yes, the paragraph about oil and gratuitous anticlericalism was just added because it is interesting in its own right. But I would argue we have reasonable grounds to assume salad of raw green lettuce dressed with garlic or onions and maybe vinegar, but not oil, may well have been a fairly common dish on medieval tables.
Meister Eberhard is a recipe collection that belongs into a south German context, most likely associated with the court of Bayern-Landshut during its ascendancy in the first half of the 15th century. We know nothing about the putative author other than that he claims he was part of the kitchen staff there. The text contains an eclectic mix of recipes and dietetic advice heavily cribbed from a variety of sources, including the (unattributed) writings of St Hildegardis Bingensis. The text is published in A. Feyl: Das Kochbuch Meister Eberhards. Diss. Freiburg i.B. 1963 and online on the website of Thomas Gloning.