309

Year 309 was a common year starting on Saturday of the Julian calendar. In the Roman Empire, it was known as the Year of the Consulship of Licinianus and Constantius. The denomination 309 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.

Events

Gaius Ceionius Rufius Volusianus, the Praetorian Prefect of Emperor Maxentius, defeats the usurper Domitius Alexander and purges Africa of his supporters.
Persia
King Hormizd II, ruler of the Sassanid Empire, demands that the king of the Ghassanids pays tribute. After the king refuses, Hormizd invades Ghassanid territory. The Ghassanids seek aid from Maximinus Daza, but before a Roman army can arrive, Hormizd defeats the Ghassanid army and kills their king. A Ghassanid force then ambushes Hormizd's small retinue while the latter is on a hunting trip, and the Sasanian king is mortally wounded. He dies after a 7-year reign.
Hormizd is succeeded by his infant son Shapur II following the brief reign and murder of Adur Narseh.
By topic

Pope Marcellus I is banished from Rome by Emperor Maxentius.
April 18 - Eusebius succeeds Marcellus I as the 31st pope, but is himself banished on August 17 to Sicily.