 In 407, Constantine III declared himself "emperor of the West" and withdrew his legions to Gaul.The Byzantine historian Zosimus () stated that Constantine's neglect of the area's defense against Irish and Saxon raids and invasions caused the Britons and Gauls to fully revolt from the Roman Empire, rejecting Roman law and reverting to their native customs.In any case, Roman authority was greatly weakened following the Visigoths' sack of Rome in 410.