Tetrarchy

Roman emperor from 306 to 337 and first to convert to Christianity (272–337)

Diocletian ( ; ; ; 242/245 – 311/312), 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. As with other Illyrian soldiers of the period, Diocles rose through the ranks of the military early in his career, serving under Aurelian and Probus, and 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 C

Roman emperor (250-306)

Valerius Licinianus Licinius (; Greek: Λικίνιος; c. 265 – 325) 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 (AD 324), and was later executed on the orders of Constantine.

Roman emperor (316-340)

Maximian (; ), nicknamed Herculius, was Roman emperor from 286 to 305. He was Caesar from 285 to 286, then Augustus from 286 to 305. He shared the latter title with his co-emperor and superior, Diocletian, whose political brain complemented Maximian's military brawn. Maximian established his residence at Trier but spent most of his time on campaign. In late 285, he suppressed rebels in Gaul known as the Bagaudae. From 285 to 288, he fought against Germanic tribes along the Rhine frontier. Together with Diocletian, he launched a scorched earth campaign deep into Alamannic territory in 288, refo

Galerius Valerius Maximianus (; Greek: Γαλέριος; 258 – May 311) was Roman emperor from 305 to 311. He participated in the system of government later known as the Tetrarchy, first acting as caesar under Emperor Diocletian. In this period Galerius obtained victory warring against the Persian Sasanian Empire, defeating Narseh at the battle of Satala in 298 and possibly sacking the Sasanian capital of Ctesiphon in 299. He also campaigned across the Danube against the Carpi, defeating them in 297 and 300. Galerius was promoted to augustus upon the abdication of Diocletian in 305, but had to contend

Marcus Aurelius Valerius Maxentius ( 283 – 28 October 312) was a Roman emperor from 306 until his death in 312. Despite ruling in Italy and North Africa, and having the recognition of the Senate in Rome, he was not recognized as a legitimate emperor by his fellow emperors.

The Tetrarchy was the system instituted by Roman emperor Diocletian to govern the ancient Roman Empire by dividing it between two emperors, the augusti, and their junior colleagues and designated successors, the caesares. It was kept in place between AD 293 and 324.

early 4th century Roman emperor

Roman emperor from 310 to 313

early 4th-century Roman emperor

Roman emperor from 316 to 317

Flavius Julius Crispus (; 300 – 326) 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

Marcus Aurelius Mausaeus Carausius (died 293) was a military commander of the Roman Empire in the 3rd century. He was a Menapian from Belgic Gaul, who usurped power in 286, during the Carausian Revolt, declaring himself emperor in Britain and northern Gaul (Imperium Britanniarum). He did this only 13 years after the Gallic Empire was ended in 273. He held power for seven years, fashioning the name "Emperor of the North" for himself, before being assassinated by his finance minister Allectus.

Junior Roman emperor from 351 to 354

Allectus (died 296) was a Roman-Britannic usurper in Britain and northern Gaul from 293 to 296.

Bagaudae (also spelled plu. bacaudae or bacauda singular) were groups of peasant insurgents in the western parts of the later Roman Empire, who arose during the Crisis of the Third Century and persisted until the very end of the Western Empire, particularly in the less-Romanised areas of Gallia and Hispania. They were affected by the depredations of the late Roman state, wealthy landowners, and clerics.

usurper of the Roman Empire

Roman caesar from 317 to 324

porphyry sculpture group of four Roman emperors outside the St Mark's Basilica in Venice, Italy

Roman usurper in 297 AD

Roman usurper

overview about the civil wars of the Tetrarchy

one time potential Caesar of the Roman Empire

son of the Roman emperor Flavius Valerius Severus

lists of political institutions of ancient Rome

son of the Roman Emperor Galerius

early 3rd-century Roman tribunus and usurper from Antioch

Council of Carnuntum