 His son and heir was William de Giffard of Yester, who was sent on a mission to England in 1200 and who also witnessed several charters of William, 'The Lion'.In 1244 he was one of the guarantees of a treaty with England, when he must have been a good age.His son, Hugh de Giffard of Yester (2), was one of the Guardians of Alexander III of Scotland and his Queen; and one of the Regents of the Kingdom appointed by the Treaty of Roxburgh dated 20 September 1255.