 By the middle of 310 AD , Galerius had become too ill to involve himself in imperial politics . His final act survives : a letter to the provincials posted in Nicomedia on 30 April 311 AD , proclaiming an end to the persecutions , and the resumption of religious toleration . He died soon after the edict 's proclamation , destroying what little remained of the tetrarchy . Maximinus mobilized against Licinius , and seized Asia Minor . A hasty peace was signed on a boat in the middle of the Bosphorus . While Constantine toured Britain and Gaul , Maxentius prepared for war . He fortified northern Italy , and strengthened his support in the Christian community by allowing it to elect a new Bishop of Rome , Eusebius . 
