The Invitation to William was a letter sent by seven notable English nobles, later called "the Immortal Seven", to stadtholder William III, Prince of Orange, received by him on 30 June 1688 (Julian calendar, 10 July Gregorian calendar). In England, the heir apparent to the throne, James Francis Edward Stuart, had just been born to the unpopular King James II of England, and baptised a Catholic. The letter asked William, who was a nephew and son-in-law of James II, to use military intervention to force the king to make his eldest daughter, Mary, William's Protestant wife, his heir. The letter alleged that the newborn prince was an impostor.