Reddit mentions of Imperium: A Novel of Ancient Rome

I'm reading two at once, both are polar opposites of each other, but fantastic reads!

Imperium: A Novel of Ancient Rome by Robert Harris

My Grandmother Asked Me to Tell You She's Sorry by Frederik Backman

I think someone already mentioned Julian by Gore Vidal. This would be an interesting topic, as the novel concerns Julian the Apostate. You could have a very interesting debate on the birth of the modern Christian faith. You could also include episodes 3, 4 and 5 of Twelve Byzantine Rulers, a very popular podcast and quite a good introduction to the "Eastern Roman Empire"; a topic sadly much overlooked in most history schooling.

The Cicero books of Robert Harris (author of excellent "What if Germany won WWII" novel Fatherland, itself a great potential for discussing what "could have been"), would make a good start for discussing the fall of the Roman Republic. There are two books in a triology currently published; Imperium and Conspirata, also published as Lustrum.

Apart from Ancient history, if you want to consider American history, you could try the wonderful novels of E. L. Doctorow. His Ragtime is often included in lists of "best American novels" and deals with racism, the early years of Jazz, includes many famous American persons and of course fictional characters. Another one of his is The March which might be rather topical at the moment, as it deals with Sherman's March to the Sea during the American Civil War. Very good reading (as most of Doctorow is) and not too long either.