Sir William's great-great-great-grandson, Sir Robert Howard, married Lady Margaret Mowbray, elder daughter of Thomas Mowbray, 1st Duke of Norfolk (1366–1399). The Mowbray line of Dukes died out in 1476 and the heiress of the last Duke, Anne Mowbray, died at the age of nine in 1481; after declaring her widower King Edward IV's son Richard of Shrewsbury, 1st Duke of York, illegitimate, Richard III of England created the son of Sir Robert and Lady Margaret, John Howard, 1st Duke of Norfolk, of a new creation on 28 June 1483, the 200th anniversary of the Barony of Mowbray to which he was also senior co-heir. John had previously been summoned to Parliament as Lord Howard by Edward IV. He was also created hereditary Earl Marshal. John's son and heir, Thomas Howard, 2nd Duke of Norfolk, was the grandfather of two English queens, Anne Boleyn and Catherine Howard, both wives of Henry VIII.