1st Lord Leyburn. He did homage on November 7, 1271. His father’s bailiwick of Inglewood forest was confirmed to him on May 18, 1272. He was summoned for service against the Welsh in 1277. His father had been in dubt to the Jews, but William asserted in one case that the bond produced was a forgery. In 1278 he granted to the King and Queen Leeds Castle, which his father had acquired, and in the following year he received pardon for all debts due by him or his father. He was probably employed in Gascony. In June, 1294, he was given the custody of Pevensey Castle, and on June 7 he was made “captain of the King’s sailors and mariners in the Cinque Ports. . .” He and John Botetourt were admirals of the fleet sent to Guienne in December, 1295. In 1298 and later he was summoned for service in Scotland. He was summoned to Parliament from February 6, 1298/99, to December 12, 1309, by writs directed Willelmo de Leyburn, whereby he is held to have become lord Leyburn. He was at the siege of Carlaverock in July, 1300, and in Scotland again in 1303 and 1304. He attended the coronation of Edward II on February 25, 1307/08.
William de Layburn 
