Jews Were Plentiful in the Dark Ages

Reading Michael Chabon's "Gentlemen of the Road" a few weeks ago led me to realize that, in the Dark Ages in which the novel was set, there were all kinds of Jews. The protagonists in the novel are from Regensburg and Ethiopia, both Jews but as phenotypically and culturally diverse as you could hope to find. They get involved with an adventure in the Kaganate of the Khazars, also Jews, albeit converts. Their story intertwines with that of some Radanite Jews, far ranging traders. There are elephants, but I couldn't tell if they were Jewish or not.

I wonder why I wasn't more aware of the presence and activities of so many kinds of Jews in medieval Europe and Central Asia. I have always been an avid reader of medieval history, and it seems to me that Jews usually just get thrown as as a mention. Kind of like how African Americans would get a brief mention in American history texts. There were African slaves, then they were freed. Some did well, eg Booker T. Washington and Geo Washington Carver. Medieval Jews seem to be around in history books just to lend money and to be victimized. Otherwise, it is as if they had no significant impact on history, something I doubt very much was the case.

Maybe I'm just more of an ignoramus than I realized, and I've just read the wrong books.