"The History of the Decline and Fall of the Roman Empire" traces Western civilization (as well as the Islamic and Mongolian conquests) from the height of the Roman Empire to the fall of Byzantium in the fifteenth century.
The six volumes cover the history, from 98 to 1590, of the Roman Empire, the history of early Christianity and then of the Roman State Church, and the history of Europe, and discusses the decline of the Roman Empire among other things.
Gibbon offers an explanation for the fall of the Roman Empire, a task made difficult by a lack of comprehensive written sources, though he was not the only historian to attempt it.
According to Gibbon, the Roman Empire succumbed to barbarian invasions in large part due to the gradual loss of civic virtue among its citizens.
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.

Edward Gibbon FRS (8 May 1737 – 16 January 1794) was an English historian, writer, and member of parliament.