Lucius Domitius Alexander (d. ca. 311), probably born in Phrygia, was vicarius of Africa when Emperor Maxentius ordered him to send his son as hostage to Rome. Alexander refused and proclaimed himself emperor in 308.
The most detailed if somewhat confusing description of the insurrection is given by Zosimos (II, 12 and 14). He reports that Maxentius sent his portrait to Africa to gain recognition as emperor there. The troops resisted because of their loyalty to Galerius. Maxentius ordered Domitius Alexander, the governor of the province, to send his son to Rome to secure his loyalty. Alexander refused and was crowned emperor by his army. The incident was probably caused by the conflict between Maxentius and his father Maximian early in 308, and Zosimos confused Galerius with Maximian in his account.
Apart from the province of Africa, Domitius Alexander also controlled Sardinia. At the time of his accession, he was already at an advanced age. There is evidence in an inscription (CIL viii, 22183) that Alexander and Constantine I allied themselves in opposition to Maxentius. Salama suggests that, at the latest, the pact was entered into by autumn of 310.
Maxentius sent his praetorian prefect Rufius Volusianus and a certain Zenas to quell the rebellion, and Alexander was taken prisoner and then executed by strangulation. Apparently, his troops did not offer much resistance. Maxentius retaliated with confiscations of the property of alleged supporters of Alexander. The year of the end of Alexander's reign is subject to debate; dates ranging from 309 to 311 have been proposed.