William was the only child of William II, Prince of Orange and Princess Mary (1631-1660), eldest daughter of Charles I of England. He was born at The Hague in Holland on 4 November 1650, a few days after his father's death. In 1677 he married his cousin Princess Mary at St James's Palace in London and they returned to live in Holland. Although a Protestant herself, Mary's father, who succeeded as James II in 1685, was a Roman Catholic and not popular in England because of his religion. When he had a son the English authorities did not want another Roman Catholic monarch so in 1688 they called on William to come to England and march against James to take the throne and reign jointly with Mary. However, before William reached London James had fled to France. William III and Mary II were crowned as joint monarchs in the Abbey on 11 April 1689. The King was popular with Irish Protestants following his victory at the battle of the Boyne but he was never well liked in England. The Act of Succession, passed during this reign, ensured that only a Protestant would succeed to the throne. He was devastated when Mary died in 1694. There were no children and he himself died on 8 March 1702, the throne passing to Mary's sister Anne. His death was caused by a fall from his horse which had stepped in a mole-hill. The 'little gentleman in black velvet' (the mole) was therefore praised by his enemies. William was buried with his wife in a vault beneath the south aisle of Henry VII's Lady Chapel, not far from his mother's grave. Although a monument was designed for them it was never erected. In 1725 the Abbey acquired life-size wax effigies of the king and queen and these are on display in the Museum. That to William is a remarkable portrait.

Photographs of the wax effigies can be purchased from Westminster Abbey Library.

In 1689 Mary (James II's daughter) and her cousin and husband William of Orange jointly succeeded to the throne. For the first time the country had both a King and a Queen (neither were consorts) and their joint coronation was held in Westminster Abbey in April 1689.

William used the original Coronation Chair whilst Mary used a specially made replica for her investiture and crowning. During the investiture, however, their Coronation Rings were mixed up and Mary's ruby ring was mistakenly placed on William's finger.