 Ramsbury's diocese was created from the northwestern territory of the bishop of Winchester in 909.In about 705 the vast diocese of Wessex at Winchester was divided in two with the creation of a new diocese of Sherborne under Bishop Aldhelm, covering Devon, Somerset and Dorset.Cornwall was added to the diocese at the end of the ninth century, but in about 909 the diocese was divided in three with the creation of the bishoprics of Wells, covering Somerset, and Crediton, covering Devon and Cornwall, leaving Sherborne with Dorset.