After the abdication of Diocletian and Maximian in 305 and a series of civil wars between rival claimants to imperial power, during the years 306–313, the Tetrarchy was abandoned. Constantine the Great undertook a major reform of the bureaucracy, not by changing the structure but by rationalising the competencies of the several ministries during the years 325–330, after he defeated Licinius, emperor in the East, at the end of 324. The so-called Edict of Milan of 313, actually a fragment of a letter from Licinius to the governors of the eastern provinces, granted freedom of worship to everyone, including Christians, and ordered the restoration of confiscated church properties upon petition to the newly created vicars of dioceses. He funded the building of several churches and allowed clergy to act as arbitrators in civil suits (a measure that did not outlast him but which was restored in part much later). He transformed the town of Byzantium into his new residence, which, however, was not officially anything more than an imperial residence like Milan or Trier or Nicomedia until given a city prefect in May 359 by Constantius II; Constantinople.