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 300s decade ran from January 1, 300, to December 31, 309.
The 310s decade ran from January 1, 310, to December 31, 319.
The 320s decade ran from January 1, 320, to December 31, 329.
Year 325 (CCCXXV) was a common year starting on Friday of the Julian calendar. At the time, it was known as the Year of the Consulship of Proculus and Paulinus. The denomination 325 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.
The 270s decade ran from January 1, 270, to December 31, 279.
Year 313 (CCCXIII) was a common year starting on Thursday of the Julian calendar. At the time, it was known as the Year of the Consulship of Constantinus and Licinianus. The denomination 313 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. This year is notable for ending of the persecution of Christians in the Roman Empire.
Year 305 (CCCV) was a common year starting on Monday of the Julian calendar. At the time, it was known as the Year of the Consulship of Constantius and Valerius. The denomination 305 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.
The 290s decade ran from January 1, 290, to December 31, 299.
The 280's decade ran from January 1, 280, to December 31, 289.
Year 293 (CCXCIII) was a common year starting on Sunday of the Julian calendar. In the Roman Empire, it was known as the Year of the Consulship of Diocletian and Maximian. The denomination 293 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 307 (CCCVII) was a common year starting on Wednesday of the Julian calendar. At the time, it was known as the Year of the Consulship of Severus and Maximinus. The denomination 307 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 311 (CCCXI) was a common year starting on Monday of the Julian calendar. At the time, it was known as the Year of the Consulship of Valerius and Maximinus. The denomination 311 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.
Year 317 (CCCXVII) was a common year starting on Tuesday of the Julian calendar. At the time, it was known as the Year of the Consulship of Gallicanus and Bassus. The denomination 317 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.
The Battle of Cibalae was fought in 316 between the two Roman emperors Constantine I and Licinius. The site of the battle, near the town of Cibalae in the Roman province of Pannonia Secunda, was approximately 350 kilometers within the territory of Licinius. Constantine won a resounding victory, despite being outnumbered.
The Battle of Mardia, also known as Battle of Campus Mardiensis or Battle of Campus Ardiensis, was fought in late 316/early 317 between the forces of Roman Emperors Constantine I and Licinius. Its location was probably modern Harmanli (Bulgaria) in Thrace.
Aurelius Valerius Valens, rarely enumerated as Valens I, was briefly Roman emperor from late 316 to early 317. He was proclaimed emperor by Licinius, emperor of the East, during his war against Constantine I, emperor of the West.
Bassianus was a Roman senator, whom the Emperor Constantine I arranged to marry his half-sister, Anastasia. In 314 Constantine hoped to elevate Bassianus to the imperial rank of caesar, but Constantine's co-augustus in the East Licinius successfully opposed the move. According to the Anonymus Valesianus, a Latin chronicle composed during late antiquity, Bassianus was accused of plotting against the throne and was executed by Constantine.
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.
