Diocletian (Latin: Gaius Aurelius Valerius Diocletianus Augustus) was a Roman emperor from 284 to 305. Born to a family of low status in the Roman province of Dalmatia, Diocletian rose through the ranks of the military to become cavalry commander to the Emperor Carus. After the deaths of Carus and his son Numerian on campaign in Persia, Diocletian was proclaimed emperor. Diocletian’s reign stabilized the empire and marks the end of the Crisis of the Third Century.

Diocletian separated and enlarged the empire’s civil and military services and reorganized the empire’s provincial divisions, establishing the largest and most bureaucratic government in the history of the empire.

Diocletian’s reforms fundamentally changed the structure of Roman imperial government and helped stabilize the empire economically and militarily, enabling the empire to remain essentially intact for another hundred years despite being near the brink of collapse in Diocletian’s youth. Weakened by illness, Diocletian left the imperial office on 1 May 305, and became the first Roman emperor to abdicate the position voluntarily. He lived out his retirement in his palace on the Dalmatian coast, tending to his vegetable gardens. His palace eventually became the core of the modern-day city of Split.