Wilhelm I.
Wilhelm I is the name of the following people:
- Wilhelm I (German Empire) , King of Prussia (1861–1888), German Emperor (1871–1888), also Wilhelm I (Prussia)
- William I (England) , the Conqueror , King (1066-1087)
- William I (Sicily) , King (1154–1166)
- William I (Scotland) , the Lion , King (1165–1214)
- Wilhelm I (Netherlands) , King (1815–1840), also Wilhelm I (Luxembourg)
- Wilhelm I (Württemberg) , King (1816–1864)
- William I de la Roche , Duke of Athens (1280–1287)
- Wilhelm I (Bavaria) , Duke (1347–1389)
- Wilhelm I (Braunschweig-Wolfenbüttel) , Duke (1416–1482)
- Wilhelm I (Hesse) , the Elder , Landgrave (1471–1493)
- Wilhelm I (Hessen-Kassel) , Elector (1802–1806, 1813–1821)
- Wilhelm I (Nassau) , Duke (1816–1839)
- Wilhelm I (Montferrat) , margrave (890)
- William I (Provence) , the liberator , margrave (970–993)
- Wilhelm I of Champlitte , Prince of Achaea (1205–1209)
- Wilhelm I (Meißen) , the one-eyed , margrave (1349–1407)
- Wilhelm I (Orange) , the silent prince (1559–1584)
- William I (Aquitaine) , Count of Auvergne (893–918)
- Wilhelm I (Montferrat) , Count († before 933)
- William I (Normandy) , long sword , Count of Rouen († 942)
- Wilhelm I of Apulia , Count (1043-1046), see Wilhelm Eisenarm
- Wilhelm I (Besalú) the Fat , Count († 1052)
- Wilhelm I (Flanders) , Count (1127–1128)
- Wilhelm I (Jülich) , Count (1142–1176)
- Wilhelm I (Holland) , Count (1203–1222)
- Wilhelm I (Berg) , Count (1296–1308)
- Wilhelm I. (Katzenelnbogen) († 1331), Count
- Wilhelm I of Limburg-Broich , Count of Limburg (1400–1442)
- Wilhelm (Nassau) , the Rich , Count of Nassau-Dillenburg (1516–1559)
- Wilhelm I of Utrecht , Prince-Bishop (1054-1076)
- Wilhelm I of Diepholz († 1242), Bishop of Minden
- Wilhelm I von Holte , bishop and regent of Münster (1259–1260)
Church rulers:
- Wilhelm I of Lebus , bishop (1252–1273)
- Wilhelm I. Sölner , Abbot of Ebrach Monastery (1714–1741)