The Diocese of Winchester forms part of the Province of Canterbury of the Church of England. Founded in 660 AD, it is one of the oldest dioceses in England. With its see city at Winchester, it once covered the Kingdom of Wessex, many times its present size. As other dioceses were erected in its territory, today it covers most of the historic enlarged county of Hampshire. The 11th century Winchester Cathedral is the mother church of the diocese, the seat of the Bishop of Winchester.