Civil wars of the Tetrarchy in the context of "Usurper"

Constantine I (27 February 272 – 22 May 337), also known as Constantine the Great, or known mononymously as Constantine, was Roman emperor from AD 306 to 337 and the first Roman emperor to convert to Christianity. He played a pivotal role in elevating the status of Christianity in Rome, the Edict of Milan decriminalising Christian practice and ceasing Christian persecution. This was a turning point in the Christianisation of the Roman Empire. He founded the city of Constantinople (now Istanbul) and made it the capital of the Empire, which it remained for over a millennium.

Born in Naissus, a city located in the province of Moesia Superior (now Niš, Serbia), Constantine was the son of Flavius Constantius, a Roman army officer from Moesia Superior, who would become one of the four emperors of the Tetrarchy. His mother, Helena, was a woman of low birth, probably from Bithynia. Later canonised as a saint, she is credited for the conversion of her son in some traditions, though others believe that Constantine converted her. He served with distinction under emperors Diocletian and Galerius. He began his career by campaigning in the eastern provinces against the Persians, before being recalled to the west in AD 305 to fight with his father in the province of Britannia. After his father's death in 306, Constantine was proclaimed as augustus (emperor) by his army at Eboracum (York, England). He eventually emerged victorious in Civil wars of the Tetrarchy against the emperors Maxentius and Licinius to become the sole ruler of the Roman Empire by 324.

Marcus Aurelius Valerius Maxentius (c. 283 – 28 October 312) was a Roman emperor from 306 until his death in 312. Despite ruling in Italy and North Africa, and having the recognition of the Senate in Rome, he was not recognized as a legitimate emperor by his fellow emperors.

He was the son of former Emperor Maximian and the son-in-law of Emperor Galerius. The latter part of his reign was preoccupied with civil war, allying with Maximinus against Licinius and Constantine. The latter defeated him at the Battle of the Milvian Bridge in 312, where Maxentius, with his army in flight, purportedly perished by drowning in the Tiber river.

Galerius Valerius Maximinus, born as Daza (Ancient Greek: Μαξιμίνος; 20 November c. 270 – c. July 313), was Roman emperor from 310 to 313. In 305 his uncle Galerius admitted him to the Tetrarchy with the rank of caesar, a controversial appointment which helped start the civil wars of the Tetrarchy in the following year. Maximinus Daza claimed the title of augustus in 310, sharing and often contesting power with Licinius. A committed pagan, he engaged in one of the last persecutions of Christians, and was the last person to hold the title of Pharaoh of Egypt. In 313 Maximinus Daza openly turned against Licinius and was routed at the Battle of Tzirallum. He died during the subsequent retreat, shortly after publishing an edict of tolerance restoring the Christians' freedoms.

The Battle of Tzirallum was part of the civil wars of the Tetrarchy fought on 30 April 313 between the Roman armies of emperors Licinius and Maximinus. The battle location was on the "Campus Serenus" at Tzirallum, identified as the modern-day town of Çorlu, in Tekirdağ Province, in the Turkish region of Eastern Thrace. Sources put the battle between 18 and 36 Roman miles from Heraclea Perinthus, the modern-day town of Marmara Ereğlisi.

Constantine I (Gaius Flavius Valerius Constantinus, 27 February 272 – 22 May 337), also known as Constantine the Great, or known mononymously as Constantine, was Roman emperor from AD 306 to 337 and the first Roman emperor to convert to Christianity. He played a pivotal role in elevating the status of Christianity in Rome, the Edict of Milan decriminalising Christian practice and ceasing Christian persecution. This was a turning point in the Christianisation of the Roman Empire. He founded the city of Constantinople (now Istanbul) and made it the capital of the Empire, which it remained for over a millennium.

Born in Naissus, a city located in the province of Moesia Superior (now Niš, Serbia), Constantine was the son of Flavius Constantius, a Roman army officer from Moesia Superior, who would become one of the four emperors of the Tetrarchy. His mother, Helena, was a woman of low birth, probably from Bithynia. Later canonised as a saint, she is credited for the conversion of her son in some traditions, though others believe that Constantine converted her. He served with distinction under emperors Diocletian and Galerius. He began his career by campaigning in the eastern provinces against the Persians, before being recalled to the west in AD 305 to fight with his father in the province of Britannia. After his father's death in 306, Constantine was proclaimed as augustus (emperor) by his army at Eboracum (York, England). He eventually emerged victorious in Civil wars of the Tetrarchy against the emperors Maxentius and Licinius to become the sole ruler of the Roman Empire by 324.