Diocletian’s resignation in A.D. 305 was followed by a period of
confusion and civil war, which ended in the establishment of Constantine
as sole emperor in A.D. 323. He was son of one of the co-emperors and
the Empress Helena. Constantine made an important change in the
government by separating the military power from the civil authority.
The influence of the _Legati_ (provincial viceroys) was thus reduced,
and the fact that the emperor alone held both the civil and military
power gave him a great predominance.