Roma Eterna by Robert Silverberg
Only 3 people out of the 13 who showed up for the discussion had finished this alternate history collection of short stories. One person hadn’t read any of the book and 4 did not plan to finish it. Almost everyone (12 people) had read Silverberg before.
Although the book is marketed as a novel, it is actually a collection of stories (most published previously in Asimov’s). The stories are related only by the theme of a Rome that continues eternally (or at least through the last story which is set in 2723A.D.), but is often on the verge of falling. Silverberg’s history roughly