William Parr, 1st Marquess of Northampton, 1st Earl of Essex, 1st Baron Parr KG (14 August 1513 – 28 October 1571), was the only brother of Queen Catherine Parr, the sixth and final wife of King Henry VIII. He was a "sincere, plain, direct man, not crafty nor involved", whose "delight was music and poetry and his exercise war" who co-authored a treatise on hare coursing. He was in favour with the first two successive Protestant Tudor monarchs, Henry VIII and his son Edward VI, under whom he was the leader of the Protestant party, but having supported the desire of the latter to be succeeded by the Protestant Lady Jane Grey, was attainted by the Catholic Queen Mary (Edward VI's half-sister and successor), but was restored by her half-sister and Protestant successor Queen Elizabeth I. He mar