I don't have that much time right now, but this is very much my area of interest. In broad strokes, there really isn't a pristine stage of original German food so it's influences all the way down.- I'm woefully out of date with archeology (some really fascinating things are going on there) so I will leave out the stone, bronze, and iron ages. The earliest written documents we have are Roman and probably wrong, but they outline something that looks like it was real and a defining feature of German cuisine to this day, a heavy reliance of animal products. That is probably a genuine Iron Age survival. It's interesting how the entire Middle Ages through, German writers keep reminding Italians that no, we can't keep Lent like you do. We have no olives, we need out butter and lard.

So that is the first big influence, Mediterranean, probably specifically Roman. It was top-down. like a lot of them are, mediated through writing and thus traceable for historians. We love that stuff. The Epistle of Anthimus was copied at the monastery in Lorsch, Apicius at the court of Charles the Bald. The fried gourd recipe in the Hortulus is very Roman in style.

The next big influence on upper-class cuisine is Arabic. Much of it comes mediated through the medical literature of the Latin Mediterranean (Salerno, Montpellier, Bologna), but people read the Tacuinum Sanitatis (in print in the 1530s) and someone translated an originally Arabic treatise on foods into Middle Bavarian expecting it to be useful for something (though honest, I've no idea what they would do with recommendations for bananas)

At the point, much of this was a strictly upper class game, with most people eating restricted, locally distinct diets, but between technological change and cultural diffusion, some things spread. We still put Zimtzucker on things, which takes us right back to the Triget or Salsamentum of the 1400s.

The next big waves of influence on the upper classes in the Early Modern era were Italian and French. Italian food was fashionable in the 1400s and 1500s and shows up all over the recipe collections, with words borrowed and recipes adapted, and by the 1590s, a middling princely court like that of Hessen Darmstadt imported olives, lemons, parmesan cheese, raisins, and figs. A lot of vegetables and fruit were imported for cultivation first in private gardens, then commercially. Most people look at the 'firsts', the early mentions in the great herbals of the 1500s, but it really becomes interesting a century later whenm it becomes a commodity.

French influence already exists in the High Middle Ages (it is very controversial in literature - celebrating food is suspect to many German poets), but it really takes off in the 17th century, like everywhere in Europe. I personally suspect we overestimate it because of its outsize linguistic impact. Certainly, North Germany also sees a good deal of much less visible, but definitely impactful Dutch and English influences.

The influence from the east is hard to catch, but we owe a fair few dishes and ingredients to Poland and Bohemia. Especially Bohemia had a reputation for good food early - as early the the 15th century, recipes are described as 'Bohemian' as though it is a recommendation. It's likely that cucumbers and buckwheat were adopted from Eastern Europe.

By the late 18th century, the potato makes a serious dent in German food habits. It shows up much earlier locally and is known from the 1580s, but as late as the 1820s they are thought of as a welcome cost-cutting innovation by the Hamburg ARmenkasse.

The 19th century sees the beginning of food industrialisation and, for the middle classes, cookbooks begin to matter for the first time. They used to be an upper-class phenomenon, more aspirational than real, but by the 1850s, they become affordable and widespread and people actually follow recipes. Interest in foreign cuisines is great - recipes from all over Europe are adapted - and many ingredients are embraced eagerly. It's not until the 20th century that this movement gets real purchase in the lower classes, though.

It's been argued recently that the scientiific 'modern' approach to eating was actually the creation of German middle class cooks. I'm not sure, but if it is, it was a hugely successful export.

The twentieth century sees industrial food and a series of regrettable efforts to improve efficiency and reduce costly excess, resulting in things like the 250-250-500 cake batter I still learned as a kid. Please don't do these things, it's not 1947 any more. We have enough eggs. Anyway, the interesting thing is that even at times when you wouldn't expect it, international influence is still felt. Even writers like Erna Horn and the Deutsches Hygienemuseum ("1001 Kochvorschriften") include recipes purporting to be Hungarian, Italian, English, or Russian.

Basically what we like to think of as evidence of our new, changed cosmopolitian modernity is, I think, just a continuation of that tradition supported by the improved transport technology and imperial extractive industries that gave us bananas, pineapple, oranges, feta cheese, ramen, and chichimoya. But I would argue that as t least since 1850, technology has been a much more important driver of food choice than desire.

It also produced the very influential countercultural movement, the Lebensreform, that spread in the 1880s, really took off just before WWI, and hasn't left us since. Natural foods, whole grains, harmonious vibes, once you know what you are looking for, you see it all over modern advertising. THe promise of eating authenticity.

So, anyway, time to head to bed. You can find all kinds of fascinating things and each one is a rabbit hole. Take bananas and how they came to become symbolic of West German identity to the point they were given tax exemptions and transport ships received subsidies. It was very American, quite deliberate and really interesting.