William, Count of Luxembourg

Seal of William, Count of Luxembourg. The Latin inscription on the border of the seal reads: SIGILLVM WILHELMI COMITIS DE LVCELENBVRCH William (1081–1131) was count of Luxembourg from 1096 until his death in 1131, succeeding his elder brother Henry III. They were both sons of Conrad I and Clementia of Aquitaine. William was the first of his family to use the title count of Luxembourg in his documents.

Like his predecessors, William was embroiled in debates with Bruno, the archbishop of Trier, in 1122 and 1127, leading to William's excommunication.

Around 1105 he married Matilda or Luitgarde of Northeim, daughter of Kuno, count of Beichlingen, with whom he had three children: Conrad II (died 1136), count of Luxembourg William, count of Gleiberg, documented in 1131 and in 1158 Liutgarde (1120 - 1170), married Henry II (1125 - 1211), count of Grandpré

Upon his death in 1131, William was succeeded as count of Luxembourg by his eldest son Conrad II.