The History of the Decline and Fall of the Roman Empire, by Edward Gibbon

Chapter LXIX: State Of Rome From The Twelfth Century

State Of Rome From The Twelfth Century.—Temporal Dominion Of The Popes.—Seditions Of The City.—Political Heresy Of Arnold Of Brescia.—Restoration Of The Republic.—The Senators.—Pride Of The Romans.—Their Wars.—They Are Deprived Of The Election And Presence Of The Popes, Who Retire To Avignon.—The Jubilee.—Noble Families Of Rome.—Feud Of The Colonna And Ursini.