I have wondered whether UC is a result of modern food, modern stress or what. I just ran across this article (can't read the whole thing without subscrib.) that says there are references to UC symptoms in 640 BC to 170 AD. So that's interesting.
UC was given a specific diagnosis in 1875. Crohn's was described in 1859 but not recognized as a separate entity until the 1950's.
I think one of the biggest changes is that people used to die from it. My MD told me that which was a big shock to me. I've always thought "Well at least it isn't cancer. I won't die from it" which turns out to be false.
This info from "Diseases of the Colon and Rectum" journal March 1999
journals.lww.com/dcrjournal/Citation/1999/42030/Surgery_for_ulcerative_colitis__Historical.1.aspx