 The Parr family originally came from Parr, Lancashire.Sir William's great-grandfather, Sir William de Parre (died 1405) married in 1383 Elizabeth de Ros, daughter of Sir John de Ros of Kendal and Katherine de Latimer, a daughter of Thomas, 1st Baron Latimer of Brayebrooke.Elizabeth was the granddaughter and heiress of Sir Thomas de Ros, Baron of Kendal and had livery of her inheritance.