Magnus Duke of Saxony

Magnus (c. 1045 – 23 August 1106) was the Duke of Saxony from 1072 to 1106 and the last member of the House of Billung. He rebelled against Emperor Henry IV in 1070 alongside Otto of Nordheim but was defeated, captured, and imprisoned in Harzburg until his release upon becoming duke.

In 1073, Magnus destroyed Harzburg and renewed conflict with Henry IV. Captured again at the First Battle of Langensalza in 1075, he later reconciled with Henry after saving Rudolf von Rheinfeld's life during the Battle of Mellrichstadt (7 August 1078). He fought against Slavs alongside royal forces but remained an enemy of Archbishop Adalbert of Bremen.

Magnus died in 1106. His duchy was given to Lothair of Supplinburg, and his lands were divided between his two daughters: Sophia married Béla I's daughter, and Eilika married Count Otto of Ballenstedt. Through these marriages, Magnus' lands passed to the Welf (via Wulfhilde) and Ascania (via Eilika) houses.