Sir William Sarsfield was an Irish landowner, public official and soldier of the sixteenth century.
He was knighted by Queen Elizabeth I in 1566 for his service against Shane O'Neill, the rebellious Gaelic lord of Tyrone.
His daughter Eleanor married Robert Dillon, Chief Justice of the Irish Common Pleas, thus allying the Sarsfield's with another powerful family of the Pale.
Among his many other descendants was his great-great-grandson Patrick Sarsfield, who famously fought on the Jacobite side during the Williamite War in Ireland (1689–91).
“The Court Book of Esker and Crumlin, 1592-1600" (Concluded).” The Journal of the Royal Society of Antiquaries of Ireland, vol.