Giles Thorndon (c. 1388 – August 1477) was a senior official of the English Crown in the fifteenth century, who was noted for his long and loyal service to the House of Lancaster and for his troubled and unsuccessful career as Lord Treasurer of Ireland.
Fifteenth-century Irish politics was dominated for almost thirty years by the feud between the faction of James Butler, 4th Earl of Ormonde, who served for many years as the Lord Lieutenant of Ireland, on the one side, and the faction of Richard Talbot, Archbishop of Dublin and Lord Chancellor of Ireland, backed by his brother John Talbot, 1st Earl of Shrewsbury, on the other side.
He produced a string of complaints against Ormonde and Chevir, covering a wide range of examples of corruption, bribery, maladministration, and disobedience to the Crown.
[3] Ormonde responded by calling a meeting of the Council at Drogheda, where he declared that Thorndon was deemed to have vacated his office and accused him of treasonable conspiracy with the quarrelsome and litigious Thomas FitzGerald, Prior of the Order of St. John of Jerusalem at Kilmainham.
[6] Thorndon and Prior FitzGerald fled to England, where they charged Ormonde with treason and (rather curiously) with necromancy, but the Privy Council, which was only concerned to end the feud, was unsympathetic to their complaints.
The New Yorkist regime, which was generally in favor of reconciliation with its former opponents, left him in peace: whether he maintained contacts with the exiled Henry VI or his queen, Margaret of Anjou, is unknown.