Apostolic succession
After legalisation in 313, the Church inside the Roman Empire adopted the same organisational boundaries as the empire: geographical provinces, called dioceses, corresponding to imperial governmental territorial division. The bishops, who were located in major urban centres as per pre-legalisation tradition, thus oversaw each diocese as Metropolitan bishops. The bishop's location was his "seat", or "see." The prestige of important Christian centers depended in part on their apostolic founders, from whom the bishops were therefore the spiritual successors according to the doctrine of Apostolic succession.