Who was Maxentius and why did he fight Constantine I?

Maxentius (died 312) was a Roman emperor who ruled from 306 to 312. He was the son of the emperor Maximian and was proclaimed princeps in Rome by the Praetorian Guard in 306 after being passed over for succession in the imperial tetrarchy.1

The conflict between Maxentius and Constantine I arose from their competing claims to the imperial throne following the collapse of the Roman Empire’s Second Tetrarchy. While Maxentius controlled Italy and Africa, Constantine held authority over Spain. The tension escalated as both leaders sought to consolidate power in the Western Empire.21

Driven by Maxentius’s provocations, Constantine launched an invasion of the Italian Peninsula. This civil war culminated in the Battle of the Milvian Bridge in 312, where Constantine defeated and killed Maxentius, thereby securing his position as the sole ruler of the Western Empire. Although historical sources influenced by Constantinian propaganda often depicted Maxentius as a tyrant, he is also noted for ending the persecution of Christians during his reign.21