Constantius Chlorus died in Britain A.C. 306, the year after Diocletian abdicated; and Galerius, who had married a daughter of Diocletian, naturally thought that under the circumstances he ought to become sole emperor. The legions of Gaul, however, proclaimed the son of Constantius Chlorus as Augustus in his stead; and as Constantine thus became ruler of Gaul and a power to be reckoned with, Galerius thought it best to give way so far as to grant Constantine the inferior title of Caesar. Soon afterwards Galerius conferred the title of Augustus upon Severus; and a little while after that the Eternal City was lost to Galerius through the revolt of his son-in-law Maxentius, the son of Maximian. The Senate of Rome then asked Maximian to re-assume the purple, and he and Maxentius shared the power between them, both taking the title of Augustus. Upon this Severus at the request of Galerius marched upon Rome. He was, however, defeated and slain. After being more or less expelled by his son Maxentius, Maximian in the year A.C. 308 marched to Gaul and married his daughter Fausta to Constantine; at the same time conferring upon him the title of Augustus. About this time Galerius made his friend Licinius an Augustus in the place of Severus; whereupon Maximin, the Governor of Syria and Egypt, demanded and was granted that title also. There were thus in the year A.C. 308 some half-a-dozen Roman Emperors instead of one; there being Constantine and Maximian in the west, Maxentius at Rome, and Galerius, Licinius, and Maximin elsewhere; not to mention Diocletian, who was content to remain in retirement. This decided break-up of the Roman Empire was Constantine's opportunity; and he was favourably placed, for he had a warlike and faithful people under him. Moreover by reversing so far as lay in his power as ruler of Gaul the traditional policy of Rome towards Christianity, and setting himself forward as a champion of a non-national religion which had been persecuted because it was non-national, Constantine was secure of the enthusiastic backing of all the Christians to be found in the dominions of his various rivals. In A.C. 310 Constantine either executed his father-in-law the Emperor Maximian, or caused him to commit suicide; and the first of his five rivals was disposed of. In A.C. 311 the Emperor Galerius died from disease, and Constantine's most formidable competitor, and one who undoubtedly had a better claim than himself to the position of sole emperor, thus opportunely made way for the ruler of Gaul. In A.C. 312 Constantine marched at the head of the Gauls against the Emperor Maxentius, defeated him near the Milvian Bridge outside Rome, and entered the Eternal City in triumph. Maxentius is said to have been drowned in the Tiber; and the Senate decreed that Constantine should rank as the first of the three remaining Augusti.