Commodus was probably the worst thing that had ever happened to Rome. It was not that he was worse than Caligula or Nero; only that the empire was bleeding to death and could not afford another madman. It had once been a privilege to be a citizen of Rome; now it only meant paying heavy taxes to a series of generals who managed to fight their way into power. When Commodus died, four would-be emperors scrambled for power. The winner was, ironically, a Carthaginian named Septimius Severus, a coarse, brutal but efficient soldier who re-established Rome’s military supremacy, murdered the regulation number of senators, and died a natural death after ruling for eighteen years. He advised his two sons to stick together, pay the soldiers, and forget the rest. They ignored his advice and set about trying to murder each other; Caracalla, the elder, proved to have a better grasp of the science of treachery; he invited his brother to a conference in their mother’s boudoir and had him hacked to death in his mother’s arms. Caracalla then murdered twenty thousand men he suspected of supporting his brother and instituted a reign of terror reminiscent of Marius. He surpassed most previous emperors in sheer malignancy when he went to Alexandria – against whose citizens he held a grudge – and invited most of its youths to some celebration on the parade grounds; then his soldiers surrounded them and cut them down. The one act for which he deserves credit was granting Roman citizenship to all the freedmen of the empire; but even this was probably a measure to increase the number of taxpayers. When Caracalla was murdered by his own officers, the senate was bullied into proclaiming him a god.
After that, ‘barrack emperors’ came and went with vertiginous speed, most of them assassinated. One of the few whose name is recalled by posterity was Heliogabalus (218-22 A.D.), whose name has become a synonym for peculiar vices. In fact, he was merely what we would now call a transsexual – a woman born in a man’s body. Soon after he became emperor – at the age of fifteen – he advertised for a doctor who could perform the sex-change operation, but finally settled for castration. He then married a beefy slave called Zoticus, and the ceremony was followed by a ritual defloration and honeymoon. The ‘empress’ (as he insisted on being called) then decided to become the patroness of the city’s prostitutes; he called them all together and made a speech in which he showed an exhaustive knowledge of every perversion that they might be called upon to satisfy. This interest in prostitutes soon revealed itself as a desire to take up their calling; he began to tour the city at night, offering sodomy or fellatio to the males he accosted. On one occasion he even went into a brothel, threw out all the prostitutes and settled down to satisfying all the customers himself.
After four years of this, his soldiers decided they would prefer a real emperor; Heliogabalus was murdered in the lavatory in 222 A.D. and his body tossed into the Tiber.
After this light relief, Rome returned to the serious business of conspiracy and assassination. In seventy years there were more than seventy emperors or would-be emperors. This high turnover was due to the fact that the army was now the only real power, and if the soldiers took a dislike to an emperor, they killed him. Meanwhile, the threat from the barbarians was growing. A great Persian king, Artaxerxes, overthrew the reigning Parthian dynasty and founded a new line of kings, the Sassanids. While Artaxerxes threatened Rome’s eastern frontier, the Germans and Goths poured in from the north. The beautiful queen Zenobia of Palmyra in Syria led a revolt that took three years to suppress – she was finally led off to Rome in golden chains, where she married a senator and died a Roman citizen. In Britain, invaders demolished huge sections of Hadrian’s Wall. The roads of the empire became infested with bandits again. Fields lay uncultivated. Plagues swept across the empire for fifteen years. Rome was unable to feed her peoples, for – unlike the Chinese, who had made their land fertile with canals – Italy’s food production was always low; she depended heavily on imports. Finally, from a welter of would-be emperors there emerged one remarkable man, Diocletian, who seized the throne in 284 A.D. and held on to it for twenty-one years. He set out ruthlessly to patch up the leaks in the sinking empire. He did it by sheer brute force, and most Romans would undoubtedly have preferred it to disintegrate, for Diocletian squeezed them as they had never been squeezed before. His armies flung bands of steel around the empire; but the towns and villages in which they were garrisoned had to feed them for nothing. Shipowners had to provide free passage for the army. Taxes were so high that businessmen gave up their businesses and farmers left their land untilled – until Diocletian passed laws forbidding them to retire.
Recognising that the empire was now too big and too chaotic for one man to govern, Diocletian appointed three other ‘Caesars’ to help him. The main partner was his most trusted officer Maximian, who governed the west from Milan. Diocletian governed the east from Nicomedia, in Asia Minor, which he turned into a miniature Rome. His son-in-law Galerius ruled what are now called the Balkans, while Maximian’s son-in-law, Constantius Chlorus, ruled Gaul. And finally, when he was convinced that the empire had been stuck together again, Diocletian retired and persuaded Maximian to do the same. The empire promptly began to fall apart.
The complicated struggle for succession went on for the next seven years, the main contenders being Galerius, Maxentius (who was the son of Maximian) and Constantine, the son of Constantius Chlorus (apparently so-called because his face was a bilious green). When Chlorus died in Britain, Constantine was hailed as emperor by his father’s troops. Finally, Constantine invaded Italy, fought a battle against Maxentius at the Milvian Bridge, and threw his rival’s body into the Tiber. After another dozen years of civil war, he became Constantine the Great, sole ruler of the Roman Empire.
And here we come to one of the major unsolved puzzles of history. Constantine was as unpleasant a character as we have encountered so far in the story of Rome, not merely ruthless but gratuitously cruel. One example will suffice. When he decided to get rid of his wife Fausta – daughter of Maximian and sister of Maxentius, both of whom Constantine had killed – he had her locked in her bathroom and the heating turned up until she literally steamed to death. Yet this is the man who claimed he had been converted to Christianity in rather the same manner as St Paul. He alleged that, on the eve of the battle of the Milvian Bridge, he had seen a cross in the sky and the words ‘By this sign shall ye conquer.’ Constantine went into battle with a spear turned into a cross as his standard, and conquered. From then on, Christianity became the religion of the Roman Empire. Christianity has naturally been grateful to Constantine ever since, and his biographer Eusebius explains how Constantine had prayed earnestly for a sign from God, which was given in the form of the cross. The fact remains that Constantine did not become a Christian until he was on his death bed. And a life of betrayals, perjuries and murders – including his own son – indicate that he remained untouched by the spirit of Christianity.
So why did Constantine decide to make Christianity the official religion of the empire? There are several possible explanations. One is that he did indeed see a cross in some natural cloud formation which he superstitiously took to be a ‘sign’ – we have seen that the Romans were obsessed by omens. Another possibility is that he was influenced by his mother Helena, a British princess (or, according to Gibbon, an innkeeper’s daughter), who at some point became a Christian and later made a famous pilgrimage to the Holy Land and located the cross on which Jesus was crucified. This is just possible, except that Constantine saw very little of his mother during his early manhood – he was too busy struggling for power – and in any case, does not seem to have been the sort of person who would be influenced by his mother’s ideas. Another possible explanation is that he was influenced by the death – by disease – of the ‘Caesar’ Galerius, who had persuaded Diocletian to persecute the Christians and who died believing that his illness was sent by God to punish him. Finally – and most likely – seems the explanation that Constantine thought it would be appropriately dramatic for the all-powerful conqueror to raise up the minority religion (only about one-tenth of his subjects were Christians) to a position of supreme importance.