William Donn de Burgh, 3rd Earl of Ulster and 4th Baron of Connaught, Irish noble who is Lord Lieutenant of Ireland (1331–32), is murdered at the age of 20 on June 6, 1333. His murder leads to the Burke Civil War.

De Burgh is born on September 17, 1312, the grandson of Richard Óg de Burgh, 2nd Earl of Ulster, via his second son, John, who dies in 1313. He is also Lord of Connaught in Ireland, and holds the manor of Clare, Suffolk.

De Burgh is summoned to Parliament from December 10, 1327 to June 15, 1328 by writs addressed to Willelmo de Burgh. In 1331 he is appointed Lord Lieutenant of Ireland for a year.

De Burgh marries, before November 16, 1327 (by a Papal Dispensation dated May 1, 1327), Maud of Lancaster, daughter of Henry, 3rd Earl of Lancaster and Maud Chaworth. They have only one surviving child, Elizabeth de Burgh, 4th Countess of Ulster, who is 13 months old when her father is murdered. She marries Lionel of Antwerp, third son of Edward III of England. Maud remarries Sir Ralph Ufford, Justiciar of Ireland (1344–46), and has further issue. She is said to have great influence over her second husband.

In February 1332, at Greencastle, near the mouth of Lough Foyle, de Burgh has his cousin, Sir Walter Liath de Burgh, starved to death. In revenge, Sir Walter’s sister, Gylle de Burgh, wife of Sir Richard de Mandeville, plans his assassination.

On June 6, 1333, William de Burgh is killed by de Mandeville, Sir John de Logan, and others. The Annals of the Four Masters note that “William Burke, Earl of Ulster, was killed by the English of Ulster. The Englishmen who committed this deed were put to death, in divers ways, by the people of the King of England; some were hanged, others killed, and others torn asunder, in revenge of his death.”

De Burgh’s widow, Maud, flees to England, where she remarries, is again widowed in 1346, and then becomes an Augustinian canoness at Campsey Priory in Suffolk, where she is buried. Upon his death, the various factions of the de Burghs, now called Burke, began the Burke Civil War for supremacy.

(Pictured: Arms of the House of de Burgh)