As the Church continued to expand, new churches in important cities gained their own bishop. Churches in the regions outside an important city were served by Chorbishop, an official rank of bishops. However, soon, presbyters and deacons were sent from bishop of a city church. Gradually priests replaced the chorbishops. Thus, in time, the bishop changed from being the leader of a single church confined to an urban area to being the leader of the churches of a given geographical area.