Henry IX, Duke of Bavaria

Henry IX the Black (c. 1075–1126), second son of Duke Welf I of Bavaria, gained Billung lands around Lüneburg through his marriage to Wulfhilde of Saxony around 1095. In 1106 he sought to succeed his father-in-law as Duke of Saxony, but King Henry V granted the duchy to Lothair of Supplinburg.

He succeeded his childless brother Welf II as duke in 1120 and helped bring about the Concordat of Worms in 1122. In the 1125 royal election he backed Lothair of Saxony over his own Hohenstaufen son-in-law. Abdicating in 1126 for his son Henry the Proud, he retired to Weingarten Abbey and died there on 13 December.