Julianus minted coins from the mint at Siscia (Sisak, Croatia) declaring himself as emperor and promising freedom.
It was all good publicity for Diocletian, and it aided in his portrayal of Carinus as a cruel and oppressive tyrant.
Although effective while he ruled, Diocletian's tetrarchic system collapsed after his abdication under the competing dynastic claims of Maxentius and Constantine, sons of Maximian and Constantius respectively.
The Diocletianic Persecution (303–11), the empire's last, largest, and bloodiest official persecution of Christianity, failed to eliminate Christianity in the empire; indeed, after 324, Christianity became the empire's preferred religion under its first Christian emperor, Constantine.
Under this 'tetrarchy', or "rule of four", each emperor would rule over a quarter-division of the empire.