William was the only child of William II, Prince of Orange and Princess Mary, eldest daughter of Charles I of England. He was born at The Hague in Holland on 4th November 1650, a few days after his father's death. The English authorities did not want any son of the Roman Catholic James II to become king 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 and his abdication was declared. 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.
On 4th November 1677 he married his cousin, the 15 year old Protestant Princess Mary, daughter of James II and his first wife Anne Hyde, at St James's Palace in London and they returned to live in Holland.
William III and Mary II were crowned as joint monarchs in the Abbey on 11th April 1689 – the first time this had happened in England. He used the ancient Coronation Chair during the ceremony and another chair was specially made for Mary to sit in. There were no children, the throne passing to Mary's sister Anne.
Burial and wax effigy
His death on 8th March 1702 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. In contrast to his wife's funeral his was private and simple, at the monarch's own request. But there was a long carriage procession from Kensington Palace. 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 the couple it was never erected.
In 1725 the Abbey acquired life-size wax effigies of the king and queen, possibly modelled by Mrs Goldsmith. That to William is a remarkable portrait.
The effigies of William & Mary are on show in the new Queen's Diamond Jubilee Galleries as is Mary II's coronation chair.
Oxford Dictionary of National Biography 2004
The funeral effigies of Westminster Abbey by A. Harvey and R. Mortimer, 2003 revised edition
Music and ceremonial at British coronations from James I to Elizabeth II, by M. Range, 2012
British royal...funerals music and ceremonial since Elizabeth I by M. Range 2016
Papers on the funeral are at the College of Arms in London