Magnus Billung Duke of Saxony
- Born: Abt 1045
- Marriage: Unknown
- Died: 23 Aug 1106 about age 61
Magnus (c.1045 - 23 August 1106) was the duke of Saxony from 1072 to 1106. Eldest son and successor of Ordulf and Wulfhild, a princess of Norway, he was the last member of the House of Billung.
In 1070, before he was duke, he joined Otto of Nordheim, duke of Bavaria, in rebellion against the Salian Emperor Henry IV. Otto was accused of being privy to a plot to murder the king, and it was decided he should submit to the ordeal of battle with his accuser. The duke asked for a safe-conduct to and from the place of meeting, and when this was refused he declined to appear, and was consequently deprived of Bavaria, while his Saxon estates were plundered. The rebellion lasted until it was put down in 1071 and Magnus was captured. Magnus was put up in the castle of Harzburg, the imposing imperial fortress which so inflamed the Saxon freemen. He was not released upon his accession to the Saxon duchy until seventy Swabians captured in Lüneburg were released.
In 1073, Harzburg was destroyed and the anger of Henry aroused. He renewed the conflict with Saxony once more. At the First Battle of Langensalza in 1075, Magnus was captured again. Released again, he joined Rudolf von Rheinfeld, duke of Swabia and antiking, and was present at the Battle of Mellrichstadt (7 August 1078), where he saved Rudolf's life. However, he and the Saxons never fully supported the Swabian Rudolf and he reconciled with Henry, even fighting the Slavs with the royal forces.
Magnus was an embittered enemy of the archbishop of Bremen, Adalbert, whose see he afflicted with repeated plundering raids. In 1106, the same year as Henry IV, he died. His duchy was given to Lothair of Supplinburg and his lands were split between his daughters by Sophia (married 1071), daughter of Bela I of Hungary, going thusly to the houses of Welf and Ascania, for Wulfhilde (1075 - 1126) married Duke Henry IX of Bavaria and Eilika (1080 - 16 January 1142) married Count Otto of Ballenstedt.
The House of Billung was a dynasty of Saxon noblemen in the 9th through 12th centuries.
The first known member of the house was Count Wichmann, mentioned as a Billung in 811. Oda, the wife of Count Liudolf, oldest known member of the Liudolfing House, was also a Billung.
In the 10th century, the property of the family was centered in the Bardengau around Lüneburg. In the middle of the 10th century, when the Saxon dukes of the House of Liudolfing had also become German kings, King Otto the Great entrusted more and more of his ducal authority to Hermann Billung. For five generations, the House of Billung ruled the Duchy of Saxony.
The house became extinct when Duke Magnus died in 1106 without sons; the family's property was divided between his two daughters. His daughter Wulfhild married Henry IX, Duke of Bavaria, a member of the House of Welf; his daughter Eilika married Otto, Count of Ballenstedt, a member of the Ascanian House. As a consequence, for the following decades control of Saxony was contested among Welfs and Ascanians.
The Billung dukes of Saxony were:
* Hermann, died 973
* Bernard I, died 1011
* Bernard II, died 1059
* Ordulf, died 1072
* Magnus, died 1106