He eventually made his way to northern Italy and made an imperial government, but it is not known whether he visited the city of Rome at this time.
but some modern historians state that Diocletian avoided the city, and that he did so on principle, as the city and its Senate were no longer politically relevant to the affairs of the empire and needed to be taught as much.
The Diocletianic Persecution (303–11), the empire's last, largest, and bloodiest official persecution of Christianity, did not destroy the empire's Christian community; indeed, after 324, Christianity became the empire's preferred religion under its first Christian emperor, Constantine.
In spite of these failures and challenges, 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 150 years despite being near the brink of collapse in Diocletian's youth.
Bureaucratic and military growth, constant campaigning, and construction projects increased the state's expenditures and necessitated a comprehensive tax reform.
Born to a family of low status in Dalmatia (Roman province), Diocletian rose through the ranks of the military to become Roman cavalry commander to the Emperor Carus.
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.
By March 284, Numerian had only reached Emesa (Homs) in Syria; by November, only Asia Minor.
On 20 November 284, the army of the east gathered on a hill 5 kilometres (3.1 mi) outside Nicomedia.
Diocletian's reign stabilized the empire and marks the end of the Crisis of the Third Century.