Gibbon's initial plan was to write a history "of the decline and fall of the city of Rome", and only later expanded his scope to the whole Roman Empire.

[13] Gibbon offers an explanation for the fall of the Roman Empire, a task made difficult by a lack of comprehensive written sources.

According to Gibbon, the Roman Empire succumbed to barbarian invasions in large part due to the gradual loss of civic virtue among its citizens.

[14] He began an ongoing controversy about the role of Christianity, but he gave great weight to other causes of internal decline and to attacks from outside the Empire.

[17] Edward Gibbon's central thesis in his explanation of how the Roman Empire fell, that it was due to embracing Christianity, is not widely accepted by scholars today.

[18][19] John Julius Norwich, despite his admiration for Gibbon's furthering of historical methodology, considered his hostile views on the Byzantine Empire flawed, and blamed him somewhat for the lack of interest shown in the subject throughout the 19th and early 20th centuries.

[23] Historian S. P. Foster says that Gibbon "blamed the otherworldly preoccupations of Christianity for the decline of the Roman empire, heaped scorn and abuse on the church, and sneered at the entirety of monasticism as a dreary, superstition-ridden enterprise".

The title and author have also been referenced in poems such as Noël Coward's "I Went to a Marvellous Party" ("If you have any mind at all, / Gibbon's divine Decline and Fall, / Seems pretty flimsy, / No more than a whimsy...")[independent source needed] and Isaac Asimov's "The Foundation of S.F.

Success", in which Asimov admits his Foundation series (about the fall and rebuilding of a galactic empire) was written "with a tiny bit of cribbin' / from the works of Edward Gibbon".

[27][independent source needed] Piers Brendon, who wrote The Decline and Fall of the British Empire, 1781–1997, claimed that Gibbon's work "became the essential guide for Britons anxious to plot their own imperial trajectory.