Diocletian

Diocletian ruled for twenty years (285 a. D.-305 a. D.), during which he tried to stop the decay of the Empire. Man of humble origins, born in Dalmatia, he took up a military career in which he gained the loyalty, esteem and affection of his soldiers. The competition with the other generals gave him fame. He promoted several economic and political reforms.

Since it was impossible to control the vast empire from the capital, he thought to divide it into four large districts, ruled by four supreme governors with full powers. But it was not possible to create four leaders with the same power so he decided that two of them called "Augusti" were the main leaders and the other two called "Cesari" subordinated to them. This system was called "tetrarchia", rule by four people. The capital was tranferred from Rome to Milan.
But this system failed and Diocletian, disillusioned, retired to private life in 305 a. D. After his reign rivalries and civil wars flared up again.
The other reforms he promoted were more durable: in order to stop the depopulation of the countryside, he established that the peasant son should continue his fathers' inflation activity; this was also extended to the sons of artisans . In 301 , he tried to stop by an edict which fixed the maximum price of the most important goods .
Diocletian tried also to reintroduce the pagan religion starting new persecutions against the Cristians and assuming the title of Giovio (in homage to Jupiter).
He had a political purpose, Christianism, with its ideals was contrary to the cult of the kings, while Diocletian considered himself a living god, whom everybody had to obey.