1. (“the Conqueror”) 1027–87, duke of Normandy 1035–87; king of England 1066–87 (son of Robert I, duke of Normandy).
2. Also,Willem I. (William I of Orange) (“the Silent”) 1533–84, Dutch leader, statesman, and revolutionary leader born in Germany: prince of Orange 1544–84; count of Nassau 1559–84; 1st stadholder of the United Provinces of the Netherlands 1578–84.
3. Also,Wilhelm I. (Wilhelm Friedrich Ludwig) 1797–1888, King of Prussia 1861–88; emperor of Germany 1871–88 (brother of Frederick William IV).
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.