The Tetrarchy was the system instituted by Roman emperor Diocletian in 293 AD to govern the ancient Roman Empire by dividing it between two emperors, the augusti, and their junior colleagues and designated successors, the caesares.
The 310s decade ran from January 1, 310, to December 31, 319.
The 320s decade ran from January 1, 320, to December 31, 329.
The 330s decade ran from January 1, 330, to December 31, 339.
Year 326 (CCCXXVI) was a common year starting on Saturday of the Julian calendar. At the time, it was known as the Year of the Consulship of Constantinus and Constantinus. The denomination 326 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.
Year 337 (CCCXXXVII) was a common year starting on Saturday of the Julian calendar. At the time, it was known as the Year of the Consulship of Felicianus and Titianus. The denomination 337 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.
Year 320 (CCCXX) was a leap year starting on Friday of the Julian calendar.
Valerius Licinianus Licinius was Roman emperor from 308 to 324. For most of his reign, he was the colleague and rival of Constantine I, with whom he co-authored the Edict of Milan that granted official toleration to Christians in the Roman Empire. He was finally defeated at the Battle of Chrysopolis, and was later executed on the orders of Constantine I.
Flavius Julius Crispus was the eldest son of the Roman emperor Constantine I, as well as his junior colleague (caesar) from March 317 until his execution by his father in 326. The grandson of the augustus Constantius I, Crispus was the elder half-brother of the future augustus Constantine II and became co-caesar with him and with his cousin Licinius II at Serdica, part of the settlement ending the Cibalensean War between Constantine and his father's rival Licinius I. Crispus ruled from Augusta Treverorum (Trier) in Roman Gaul between 318 and 323 and defeated the navy of Licinius I at the Battle of the Hellespont in 324, which with the land Battle of Chrysopolis won by Constantine forced the resignation of Licinius and his son, leaving Constantine the sole augustus and the Constantinian dynasty in control of the entire empire. It is unclear what the legal status of the relationship Crispus's mother Minervina had with Constantine was; Crispus may have been an illegitimate son.
The Battle of Chrysopolis was fought on 18 September 324 at Chrysopolis, near Chalcedon, between the two Roman emperors Constantine I and Licinius. The battle was the final encounter between the two emperors. After his navy's defeat in the Battle of the Hellespont, Licinius withdrew his forces from the city of Byzantium across the Bosphorus to Chalcedon in Bithynia. Constantine followed, and won the subsequent battle. This left Constantine as the sole emperor, ending the period of the Tetrarchy.
The Battle of Adrianople was fought in Thrace on July 3, 324, during a Roman civil war, the second to be waged between the two emperors Constantine I and Licinius. Licinius was soundly defeated and his army suffered heavy casualties. Constantine built up military momentum, winning further battles on land and sea, eventually leading to the final defeat of Licinius at Chrysopolis.
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.
The Battle of the Hellespont, consisting of two separate naval clashes, was fought in 324 between a Constantinian fleet, led by the eldest son of Constantine I, Crispus; and a larger fleet under Licinius' admiral, Abantus. Despite being outnumbered, Crispus won a very complete victory.
Martinian was Roman emperor from July to September 324. He was raised to the purple by the emperor Licinius, whom he had hitherto served as a senior bureaucrat, during Licinius's civil war against the emperor Constantine I. Constantine defeated both emperors and forced them to abdicate, and executed them after initially showing leniency.
The Constantinian dynasty is an informal name for the ruling family of the Roman Empire from Constantius Chlorus to the death of Julian in 363. It is named after its most famous member, Constantine the Great, who became the sole ruler of the empire in 324. The dynasty is also called Neo-Flavian because every Constantinian emperor bore the name Flavius, similarly to the rulers of the first Flavian dynasty in the 1st century.
Licinius II, also called Licinius Junior or Licinius Caesar, was the son of the Roman emperor Licinius I. He held the imperial rank of caesar between March 317 and September 324, while his father was augustus, and he was twice Roman consul. After losing a civil war, his father lost power and both he and Licinius Junior were eventually put to death.
The civil wars of the Tetrarchy were a series of conflicts between the co-emperors of the Roman Empire, starting from 306 AD with the usurpation of Maxentius and the defeat of Severus to the defeat of Licinius at the hands of Constantine I in 324 AD.
The German and Sarmatian campaigns of Constantine were fought by the Roman Emperor Constantine I against the neighbouring Germanic peoples, including the Franks, Alemanni and Goths, as well as the Sarmatian Iazyges, along the whole Roman northern defensive system to protect the empire's borders, between 306 and 336.
The siege of Byzantium was carried out some time between July and September 324 by the forces of the Roman emperor Constantine I during his Second Civil War against his rival, co-emperor Licinius. It would have been started simultaneously with the naval battle of the Hellespont in which Constantine's son and caesar Crispus defeated the Lycinian navy commanded by Admiral Abanto.
