Welf I, Duke of Bavaria

Welf I (c. 1035/1040–1101) was the son of Albert Azzo II of Este and Kunigunde of Altdorf, and founder of the younger House of Welf. He was made Duke of Bavaria by Emperor Henry IV in 1070.

In the Investiture Controversy he backed Pope Gregory VII and the anti-king Rudolf of Rheinfelden. Henry IV declared him deposed in 1077, but Welf kept his position with Bavarian and Italian support. He reconciled with Henry in 1095 and was confirmed as duke. By Judith of Flanders he fathered Welf II and Henry IX. His Bavarians were ambushed in Anatolia during the Crusade of 1101; Welf escaped but died on Cyprus while returning.