Diocletian, nicknamed Jovius, was Roman emperor from 284 until his abdication in 305. He was born Diocles to a family of low status in the Roman province of Dalmatia. Diocles rose through the ranks of the military early in his career, eventually becoming a cavalry commander for the army of Emperor Carus. After the deaths of Carus and his son Numerian on a campaign in Persia, Diocles was proclaimed emperor by the troops, taking the name Diocletianus. The title was also claimed by Carus's surviving son, Carinus, but Diocletian defeated him in the Battle of the Margus.
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.
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 250s was a decade that ran from January 1, 250, to December 31, 259.
The 280's decade ran from January 1, 280, to December 31, 289.
Year 299 (CCXCIX) 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 299 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 298 (CCXCVIII) was a common year starting on Saturday of the Julian calendar. At the time, it was known as the Year of the Consulship of Faustus and Gallus. The denomination 298 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 304 (CCCIV) was a leap year starting on Saturday of the Julian calendar. It was known in the Roman Empire as the Year of the Consulship of Diocletian and Maximian. The denomination 304 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 296 (CCXCVI) was a leap year starting on Wednesday of the Julian calendar. In the Roman Empire, it was known as the Year of the Consulship of Diocletian and Constantius. The denomination 296 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 288 (CCLXXXVIII) was a leap year starting on Sunday of the Julian calendar. In the Roman Empire, it was known as the Year of the Consulship of Maximian and Ianuarianus. The denomination 288 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 250 (CCL) was a common year starting on Tuesday of the Julian calendar. At the time, it was known as the Year of the Consulship of Traianus and Gratus. The denomination 250 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 306 (CCCVI) was a common year starting on Tuesday of the Julian calendar. At the time, it was known as the Year of the Consulship of Constantius and Valerius. The denomination 306 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 308 (CCCVIII) was a leap year starting on Thursday of the Julian calendar. It was known in the Roman Empire as the Year of the Consulship of Diocletian and (Galerius) Maximianus. The denomination 308 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 310 (CCCX) was a common year starting on Sunday of the Julian calendar. At the time, it was known as the Year of the Consulship of Andronicus and Probus. The denomination 310 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.
Flavius Valerius Constantius, also called Constantius I, was a Roman emperor from 305 to 306. He was one of the four original members of the Tetrarchy established by Diocletian, first serving as caesar from 293 to 305 and then ruling as augustus until his death. Constantius was also father of Constantine the Great, the first Christian emperor of Rome. The nickname "Chlorus" was first popularized by Byzantine-era historians and not used during the emperor's lifetime.
Galerius Valerius Maximianus was Roman emperor from 305 to 311. During his reign he campaigned, aided by Diocletian, against the Sasanian Empire, sacking their capital Ctesiphon in 299. He also campaigned across the Danube against the Carpi, defeating them in 297 and 300. Although he was a staunch opponent of Christianity, Galerius ended the Diocletianic Persecution when he issued the Edict of Toleration in Serdica (Sofia) in 311.
The Diocletianic or Great Persecution was the last and most severe persecution of Christians in the Roman Empire. In 303, the emperors Diocletian, Maximian, Galerius, and Constantius issued a series of edicts rescinding Christians' legal rights and demanding that they comply with traditional religious practices. Later edicts targeted the clergy and demanded universal sacrifice, ordering all inhabitants to sacrifice to the gods. The persecution varied in intensity across the empire—weakest in Gaul and Britain, where only the first edict was applied, and strongest in the Eastern provinces. Persecutory laws were nullified by different emperors at different times, but Constantine and Licinius' Edict of Milan in 313 has traditionally marked the end of the persecution.
