On 1 May 1169, an expedition of Cambro-Norman knights with an army of about six hundred landed at Bannow Strand in present-day County Wexford. It was led by Richard de Clare, called Strongbow due to his prowess as an archer. The invasion, which coincided with a period of renewed Norman expansion, was at the invitation of Dermot Mac Murrough, the king of Leinster.
In 1166, Mac Murrough had fled to Anjou, France, following a war involving Tighearnán Ua Ruairc, of Breifne, and sought the assistance of the Angevin king, Henry II, in recapturing his kingdom. In 1171, Henry arrived in Ireland in order to review the general progress of the expedition. He wanted to re-exert royal authority over the invasion which was expanding beyond his control. Henry successfully re-imposed his authority over Strongbow and the Cambro-Norman warlords and persuaded many of the Irish kings to accept him as their overlord, an arrangement confirmed in the 1175 Treaty of Windsor.