Blarney History.
Blarney Castle, as viewed by the visitor today, is the third to have been erected on this site. The first building in the tenth century was a wooden structure. Around 1210 A.D. this was replaced by a stone structure which had the entrance some twenty feet above the ground on the north face. This building was demolished for foundations. In 1446 the third castle was built by Dermot McCarthy, King of Munster of which the keep still remains standing.

Cormac McCarthy, King of Munster
The lower walls are fifteen feet, built with an angle tower by the McCarthys of Muskerry. It was subsequently occupied at one time by Cormac McCarthy, King of Munster, who is said to have supplied four thousand men from Munster to supplement the forces of Robert the Bruce at the battle of Bannockburn in 1314. Legend has it that the latter king gave half of the Stone of Scone to McCarthy in gratitude. This, now known as the Blarney Stone, was incorporated in the battlements where it can now be kissed.

Blarney Castle Web Site