When he arrives at the site of the unrest, Livius is horrified to find that Lucilla is behind it. She tries to persuade him to join her in making a splinter state, free of her brother's influence, but he feels that Roman civilization will collapse if it is broken into pieces. The issue is settled in an unexpected manner when Lucilla's husband calls in Rome's archenemy the Persians to help the rebelling forces fight Livius. The sight of the dreaded Persian cavalry so panics the defecting Romans that they go back over to Livius, swelling his army and allowing him to score an immense victory. The king of Armenia is killed, and Commodus sends word that Livius is to be made joint ruler of Rome. The condition for this reward, however, is that Livius is to wreak hideous punishments on the populations of the disloyal provinces. Rejecting this latest piece of brutality, Livius and Lucilla take their army to Rome and order Commodus to abdicate. He responds by bribing away the soldiers' loyalty and massacring Timonides and the population of the German colony (the latter action ensuring centuries of future hostility between Romans and Germans). The fawning Senate declares Commodus a god, and Livius and Lucilla are sentenced to be burned alive as human sacrifices to the new deity. This victory for Commodus is accompanied by a terrible private discovery – he is not of royal blood, being the product of illicit sex between his promiscuous mother Faustina Minor and the gladiator Verulus, who has since served as the emperor's bodyguard. His mind unhinged by this great shame, Commodus makes the bizarre decision of challenging Livius to a duel for the throne. The two fight with javelins in the Roman Forum, and Livius eventually runs Commodus through. The Senate hastily offer to make Livius emperor, but he refuses; the Roman government is now too corrupt for him to fix. He slips away with Lucilla, leaving Commodus' old advisers to bicker about who will take the emperor's place. A voice-over epilogue states that this political infighting continued for the rest of Roman history, leading to the imperial government's eventual collapse. The idea for "The Fall of the Roman Empire" originated with Anthony Mann who had just finished directing "El Cid" (1961). In London, while waiting for a taxi cab, he spotted an Oxford concise edition of Edward Gibbon's six-volume series "The History of the Decline and Fall of the Roman Empire" near the front window at the Hatchards bookshop.