- For other Romans of this name, see Licinius (gens).
Of Dacian peasant origin, born in Illyria, Licinius accompanied his close friend the Emperor Galerius on the Persian expedition in 297. After the death of Flavius Valerius Severus, Galerius elevated Licinius to the rank of Augustus on November 11 307. He received as his immediate command the provinces of Illyricum, Thrace and Pannonia.
In March 313 he married Constantia , half-sister of Constantine, at Mediolanum (now Milan), the occasion for the jointly-issued "Edict of Milan" that restored confiscated properties to Christian congregations though it did not "Christianize" the Empire as is often assumed. In the following month (April 30), Licinius inflicted a decisive defeat on Maximinus at Heraclea Pontica, establishing himself master of the East, while his brother-in-law, Constantine, was supreme in the West.
In 314 his jealousy led him to encourage a treasonable enterprise in favor of Bassianus against Constantine. When his actions became known, a civil war ensued, in which he was twice severely defeated— first near Cibalae in Pannonia (October 8, 314), and next in the plain of Mardia in Thrace. The outward reconciliation, which was effected in the following December, left Licinius in possession of Thrace, Asia Minor, Syria and Egypt, but added numerous provinces to Constantine's control.
In 323 Constantine, tempted by the "advanced age and unpopular vices" of his colleague, again declared war against him, and, having defeated his army at Adrianople (July 3, 323), succeeded in shutting him up within the walls of Byzantium.
The defeat of the superior fleet of Licinius by Flavius Julius Crispus , Constantine’s eldest son, compelled his withdrawal to Bithynia, where a last stand was made; the battle of Chrysopolis , near Chalcedon (September 18), resulted in his final submission. He was interned at Thessalonica under a kind of house arrest, but when he attempted to raise troops among the barbarians Constantine had him assassinated.
- De Imperatoribus Romanis website: Licinius
- [ Encyclopedia Britannica 1911:] Licinius
- Socrates Scholasticus account of Licinius' end
Galerius and Constantine I
with Galerius, Constantine I and Maximinus