Cashel in Munster is different from the other provincial royal sites in that traditionally it was regarded as Christian from its foundation. Indeed the very name is an early borrowing from the Latin castellum (fortress). The Eóganacht dynasties, that were associated with Cashel from the start, may have descended from returned emigrants of the 4th or 5th century from Wales who would have been exposed to Christianity and Roam rule. Therefore, we do not have a concentration of prehistoric ritual and burial monuments here as are found at the other provincial royal sites. It must originally have been a stone fort on a large imposing and naturally defensive rock outcrop. 

The overkings of Munster in historic times were known as kings of Cashel and presumably were inaugurated at the Rock of Cashel. Recent archaeological excavation beside Cormac’s Chapel has shown that there was a small wooden church and cemetery here from at least the 9th or 10th century. It seems that several of the kings of Cashel at this period were also ecclesiastics. In the later 10th century the Dál Cais, of whom Brian Boru was the most famous king, ousted by Eóganacht from the kingship of Cashel and in 1101 Muirchertach Ua Briain handed over the Rock of Cashel to the Church. It then became the archiepiscopal seat for the ecclesiastical province of Munster. 

The impressive group of buildings at the site includes a round tower (c. 1100), the beautiful Romanesque church known as Cormac’s Chapel (consecrated in 1134) and, squashed between them, the massive 13th century cruciform cathedral. The original secular royal site was thus submerged beneath this triumphant panoply of ecclesiastical structures, which form a unique and distinctive outline against the sky.