I just posted my translation of a 1964 article (well, 75% of it). The author, Fritz Hahn, did copious research to track cakes on spits from ancient Greece to modern Europe, identifying five "generations":
- Generation I is the ancient Greek ὁβελίας, a very large bread baked for Dionysian celebrations some time before 600 B.C. When you want to bake a bread as large as possible, you can't use some dinky oven in a cramped kitchen. You've got to go big! Find a long tree trunk, wrap your bread dough around it, and make a huge fire. There's good evidence that the Bacchanal Romans continued this tradition for many centuries, spreading it to the north. After the collapse of the Roman empire, there are no more references to bread on a spit for nearly a millenium; it shows up in Daun, Germany, in 1466. Hahn suggests that this German bread is a direct descendant of the Roman bread, but I think it's pure coincidence. Convergent evolution, if you will.
- In Generation II, the big German bread-on-a-spit gets shrunk and sweetened. Sugar was a rarity, so the yeast-dough cakes were seasoned with currants, honey, ginger, citrus peel, or other delights. The earliest attested recipe is from 1450. Modern helical chimney cakes (i.e. kürtőskalács and trdelník) are still considered Gen. II cakes in Hahn's taxonomy.
- Generation III seems like a bit of a misstep. Previous versions were secured on the spit by winding a tight helix of dough. The Gen III cake is still yeast dough, but rolled out in a big rectangular sheet, then cinnamon-rolled onto the wooden form. To keep the cake on the roll, the chef has to bind it with string, or else it would get saggy and fall off. HOWEVER, the string also restricts how much the cake-roll expands wherever it is placed, which may have led to a pleasant smooth-ridged exterior like we see today.
- Generation IV is the big shift from single-layer yeast-dough cakes to many-layer liquid-batter cakes! Hahn credits the new development to two things: the introduction of coffee (which fostered innovation wherever it went) and the 30 Years War (which occupied most of the employable men, and finally gave women access to the trade manuals and cookbooks that had long been men's secrets). The first two people to write Gen IV recipes were women! Susanna Harsdörffer, in 1582, and Maria Sophia Schellhammer, in 1692.
Šakotis is a Gen IV cake.[EDIT: oops, in modern times it is usually made in the Gen V manner]
- Generation V is what we know and love today. This version vastly improves texture by separating the eggs, beating the whites and folding them into the rest of the batter. This has the added benefit of making many thinner layers possible. Yes!