In the early months of the war against William III Sarsfield distinguished himself. He was a cavalry commander and later was promoted to major general. At the Battle of the Boyne Sarsfield rallied the defeated army led the defense of Limerick and an attack on William's artillery train at Ballyneety. Sarsfield was responsible for the negotiation of the treaty of surrender at Limerick (October 1691) and then joined the army of Louis XIV in the Spanish Netherlands where he was killed fighting the English at Neerwinden, near Landen, on August, 19, 1693.
The war that proceeded immediately following the surrender of James and the end of his revolt might well be called: Sarsfield's war. It is interesting to note that the same family is responsible for leading the Irish people into two disasters. First the revolt of 1641 and then "Sarsfield's war following the battle of the Boyne. Thus Patrick and his grandfather Rory O'Moore are responsible for motivating both Cromwell and the intensification of the Penal Laws following the Treaty of Limerick. One wonders why the Irish people followed such ruthless war lords in their support of absolutism and power?