May 31, 1443 - Margaret Beaufort, mother of the future Henry VII, is born at Bletsoe Castle, Bedfordshire. Margaret was a great granddaughter of John of Gaunt through the line descended from his children by Katheryn Swynford.
May 31, 1495 – Cecily Neville, mother of Edward IV and Richard III, dies.
May 31, 1911 - The Titanic was launched at Belfast. It was claimed that 'Not even God himself could sink this ship.'