Did they even use yeast? or did they use other leavening agents? I'm mostly asking about societies in the middle east including Egypt but would also like insight into where medieval Europeans acquired yeast.
Hi, you'll find several discussions about bread-making and yeast in this sub; here's one talking about early records. Note that bread-making (and brewing) date from prehistory, so it may be worth x-posting to our sister sub /r/AskAnthropology.