William III (of the Netherlands), in Dutch, Willem Alexander Paul Frederik Lodewijk (1817-90), king of the Netherlands and grand duke of Luxembourg (1849-90). The son of King William II, he was born in Brussel, Belgium. He succeeded to the throne upon the death of his father. In 1866 William agreed to sell the Grand Duchy of Luxembourg to France, thus nearly provoking a war between France and Prussia. An international conference held in London the following year prevented war by a treaty guaranteeing the independence of the grand duchy. William's long reign was marked by uninterrupted peace and prosperity. He was succeeded by his daughter Wilhelmina.
"William III (of the Netherlands)," Microsoft(R) Encarta(R) 98 Encyclopedia.