I was listening to a history podcast and they mentioned The Foundation series. Said the Galactic Empire and its fall was modeled on Rome, and that the Mule might have represented Mohammed and the Islamic forces that came out of Arabia.
Also, for Asimov fans, I'm reading a two-volume non-fiction work of his on the Bible. He goes through it book by book, telling you where the stories might have come from, linking them to ancient non-biblical history, etc. based on the best biblical and archaeological scholarship at the time. It's really fascinating.
An example: the two oldest versions we have of Genesis have slight differences in them. In one (I think the older) the word for God is actually the plural form, and some biblical scholars think this shows the evolution of the Hebrew religion from plural deities to monotheism.
Another: the long lineage of Jesus contained in Matthew contains some prostitutes.