Wilhelm was the younger son of the Count Palatine of the Rhine and Count of Weimar-Orlamünde,
Siegfried of Ballenstedt, and
Gertrude of Northeim. Siegfried I had inherited the estate of his stepfather and adoptive father, Count Palatine
Henry of Laach, and built Cochem Castle. In 1113 Siegfried died in battle against
Emperor Henry V. The emperor did not recognize the inheritance claims of
Siegfried II, William's older brother, and instead appointed his loyal companion
Gottfried von Calw as Count Palatine of the Rhine. Around 1115, William's mother entered into a second marriage with
Otto I, Count of Salm, who presumably acted as regent for Siegfried II. In 1124, Siegfried II died and William, still underage, succeeded him as Count of Weimar-Orlamünde, presumably also under Otto's regency. After William's uncle,
Lothar of Supplinburg was elected
King of the Romans in 1125, he put pressure on Godfrey of Calw to appoint William as Count Palatine of the Rhine. When William died, his cousin
Albert the Bear succeeded him in the County of Weimar-Orlamünde. In the County Palatine of the Rhine, his stepfather Otto was overthrown by the Hohenstaufen King
Conrad III, who first enfeoffed his own half-brother
Henry II Jasomirgott of Austria and, in the following year, his brother-in -law
Hermann von Stahleck with the County Palatine. ==References==