A monastery was founded at Lismore in 636 by St Carthach and it was named as a See at the synod of Rath Breassail in 1111. In 1127 it is recorded that Cormac MacCarthaig built two churches at Lismore- the same year as he commissioned his chapel at Cashel. The first stone castle at Lismore was probably built on the site of the early Christian monastery by King John in 1185. The Castle became an Episcopal residence in c. 1189 and continued as such until it was granted by Bishop Myler McGrath to Sir Walter Raleigh in 1589. Raleigh subsequently sold the castle to Richard Boyle, later First Earl of Cork. Following the extinction of the Cork line the castle passed to the Dukes of Devonshire, to whom it still belongs.