Dál Cais

In Irish history, a powerful Munster kingdom which rose to power in the second half of the 10th century. It peaked and fell within the reign of Brian Bóruma, who at the start of the 11th century became in effect Ireland's first high king from a dynasty other than the Uí Néill.

Originally part of the Déisi kingdom which settled in what is now eastern County Clare, the Dál Cais began its rise to power in the 9th century, largely through the strategic position it held at the lower reaches of the Shannon River. It seized the kingship of Munster in 963 by defeating the reigning Munster power the Eóganachta, and furthered its dominance in Ireland, mainly through several victories over theVikings of Limerick.

After Brian Bóruma's death the Dál Cais lost much of the authority it had gained, and reclaimed only a short time of power in the reigns of Brian's grandson, Tairdelbach Ua Briain, who died in 1086 and great-grandson, Muirchertach Ua Briain, who died in 1119.