from The American Heritage® Dictionary of the English Language, 4th Edition
- William I 1 Known as "William the Conqueror.” 1027?-1087. King of England (1066-1087) and duke of Normandy (1035-1087). He led the Norman invasion of England (1066) after being promised the English throne by his cousin Edward the Confessor. He defeated Harold at the Battle of Hastings and as king adopted a feudal constitution.
- William I 2 Prince of Orange. Known as "William the Silent.” 1533-1584. Dutch stadholder (1579-1584) who was made governor of Holland, Zeeland, and Utrecht (1559) by Phillip II of Spain. Spurred by the Spanish persecution of Protestants, he led a revolt against Spanish rule (1568-1576).
- William I 3 1797-1888. King of Prussia (1861-1888) and emperor of Germany (1871-1888) whose reign was marked by war with Austria (1866), the Franco-Prussian War (1870-1871), and the wide reforms introduced by Bismarck.
Sorry, no etymologies found.