Europe 313: Battle of Tzirallum
Constantine’s capture of Rome established his preeminence among the three Augusti. Realizing that Constantine and Licinius were colluding against him, Maximinus Daza crossed into Europe in the spring of 313 but was decisively defeated by Licinius at Tzirallum. Maximinus was the last Roman emperor to persecute Christians; following his downfall, Christianity began to emerge as the dominant religion in the empire.
29 Oct 312–24 May 337 Reign of Constantine the Great▲
In October 312 the Roman Senate proclaimed the 40-year-old Constantine as Senior Augustus, a title which was grudgingly acknowledged by his co-Augusti Licinius and Maximinus Daza. After eliminating his rivals in civil war, Constantine emerged as the sole ruler of the Roman Empire in 324 and established a great imperial residence at Byzantium, which he renamed as Constantinople. Constantine enacted numerous reforms to strengthen the empire and reorganized the Roman army into mobile units (comitatenses) and garrison troops (limitanei). As early as 312 he converted to Christianity, a faith he continued to support throughout his reign. When he fell ill and died in 337, after the second longest reign of a Roman emperor since Augustus, he was buried in the Church of the Holy Apostles in Constantinople.
3 Dec 312 Death of Diocletian▲
Diocletian’s last year seems to have been spent in some emotional discomfort as he unsuccessfully petitioned Maximinus Daza to return his daughter Valeria Galeria to him after she was banished from Maximinus’ court. Further disgraces occurred in 311/312 when Constantine ordered the destruction of statues and portraits of Maximian—most of which included Diocletian as well. In late 312 he was invited by Constantine and Licinius to attend the latter's wedding to Constantia; when his rejection on the grounds of ill health met with hostility, Diocletian drank poison, ending his own life at 68 in his retirement palace at Spalatum (Split).
Mar 313 Licinius and Constantia▲
In March 313 Constantine and Licinius met in Mediolanum (Milan), where, in accordance with their alliance, Licinius married Constantine’s half-sister Flavia Julia Constantia. In Rome Constantine had ordered the restitution of Christian property confiscated during the persecution; he now appears to have persuaded Licinius to make similar measures, as well as a proclamation of religious toleration, after his anticipated defeat of Maximinus Daza. This agreement is traditionally called the “Edict of Milan”, although no official announcement would be made until Licinius entered Nicomedia in June.
30 Apr 313 Battle of Tzirallum▲
In the spring of 313, while Licinius was still at Mediolanum, Maximinus Daza crossed the Hellespont with 70,000 men and captured Byzantium and Heraclea Perinthus. When he heard the news of the invasion, Licinius raced east to Adrianople, assembling a force of 30,000 men along the way. The two armies met at Tzirallum (Corlu) in late April, where, despite being severely outnumbered, Licinus’ veteran troops routed their opponents and compelled Maximinus to flee to Asia.