From 1942 to 1950, Isaac Asimov published a number of short stories in Astounding Magazine inspired by the History of the Decline and Fall of the Roman Empire -- a little bit of cribbin' from the works of Edward Gibbon. These were collected into volumes from 1951 to 1953, forming the Foundation Trilogy. Asimov returned to Foundation in the 1980's with a set of sequels and prequels.
The series chunks into very easily recognizable groups:
The Core Three
Foundation
Foundation and Empire
Second Foundation
The Sequels (The Quest for Earth)
Foundation's Edge
Foundation and Earth
The Prequels
Prelude to Foundation
Forward the Foundation
The first three are universally recognized as better than the later works, although I personally have always liked Prelude quite a bit as well. In any case, I'll be reading them all for the fortnightly book, in the narrative order.
Deep Purple, "The Mule", which was inspired by a reading of Second Foundation.