Massacre of Mullaghmast

The Massacre of Mullaghmast (Ár Mhullach Mhaistín) refers to the summary execution of Irish chieftains by the British military in Ireland. It probably occurred at the end of the year 1577. There is limited surviving documentation on the massacre, although documents have recently been made available at the National Library of Ireland.

Background
Francis Cosby, a soldier, and Robert Hartpole, a colonist, were both Englishmen who were granted land in the plantation of Leix (formally known as the Queen's county) in Ireland. The men befriended the native Irish, but in conjunction with the Lord deputy in Ireland plotted to kill the local Chieftains, two of whom were high-powered Ulstermen. With the help of the Lord Deputy of Ireland, they summoned 100-400 of the members of the leading families of Laois to Mullaghmast in County Kildare to perform military service. Most of these people were slaughtered, some burned at the stake.

An account of the massacre: