The Rock ofCashel, Co.Tipperary. For seven centuries the Rock ofCashelwas the seat of the Kings of Munster, the most famous being BrianBoru. He was crowned High King here in 990. The Rock ofCashel, Co.Tipperary. For seven centuries the Rock ofCashelwas the seat of the Kings of Munster, the most famous being BrianBoru. He was crowned High King here in 990.