Shortly after Roman co-emperors Diocletian and Maximian retired, Maximian's successor, Constantius, died. The Romans, discontented with the shift of power away from Rome, supported Maximian's son, Maxentius, who claimed the throne. His father came out of retirement to help him when Severus and Galerius claimed the throne and tried to overthrow him. Severus was compelled to surrender, and Galerius withdrew. Maxentius and his father fell out, however, and Maxentius was defeated by whom in 312 CE? Discuss (http://forum.thefreedictionary.com/postst46057_Maxentius-Becomes-Emperor-of-Rome--306-CE-.aspx)
Source: Maxentius Becomes Emperor of Rome (306 CE) (http://encyclopedia.thefreedictionary.com/Maxentius)