Who were Constantine I’s main rivals for control of the Roman Empire?

Following the death of his father, Constantius I, in 306, Constantine I emerged as a claimant to the throne during a period of significant political instability. His path to becoming the sole ruler of the Roman Empire involved a series of conflicts against several rivals who also held or claimed the title of Augustus.1

His primary rivals included:

• Maxentius: The son of Maximian, Maxentius seized power in Rome. He served as Constantine’s main rival for control of the Western Empire until his defeat at the Battle of the Milvian Bridge in 312.123
• Licinius: Initially an ally, Licinius ruled the Eastern Empire. Following the defeat of Maxentius, tensions grew between the two leaders. Constantine eventually defeated Licinius in 324, ending his reign and establishing Constantine as the undisputed ruler of the entire empire.1243
• Maximinus Daia: An Eastern emperor who vied for power alongside Licinius. He was eventually defeated by Licinius in 313, which helped consolidate the empire under the leadership of Constantine and Licinius.124

Other figures, such as Maximian and the usurper Domitius Alexander, also briefly challenged for power during the chaotic period following the collapse of the first tetrarchy.1