Thomond, also known as the kingdom of Limerick, was a kingdom of Gaelic Ireland, associated geographically with present-day County Clare and County Limerick, as well as parts of County Tipperary around Nenagh and its hinterland. The kingdom represented the core homeland of the Dál gCais people, although there were other Gaels in the area such as the Éile and Eóganachta, and even the Norse of Limerick. It existed from the collapse of the Kingdom of Munster in the 12th century as competition between the Ó Briain and the Mac Cárthaigh led to the schism between Thomond and Desmond. It continued to exist outside of the Anglo-Norman-controlled Lordship of Ireland until the 16th century.

Brian Boru was an Irish king who ended the domination of the High Kingship of Ireland by the Uí Néill, and possibly ended Viking invasions of Ireland. Brian Boru was mentioned in Annals of Inisfallen and Chronicon Scotorum as "Brian mac Cennétig". The name Brian of Bóruma or Brian Boru was given to him posthumously Brian built on the achievements of his father, Cennétig mac Lorcain, and especially his elder brother, Mathgamain. Brian first made himself king of Munster, then subjugated Leinster, eventually becoming High King of Ireland. He was the founder of the O'Brien dynasty, and is widely regarded as one of the most successful and unifying monarchs in medieval Ireland.