Henry I (919/921 - November 1, 955) was a member of the Ottonian dynasty and Duke of Bavaria from 948 until his death.
Henry was born in either 919 or 921 as the second son of the German King Henry the Fowler and his wife Matilda of Ringelheim. After the death of his father, the royal title passed to Henry's elder brother, Otto I, Holy Roman Emperor, who immediately had to face the indignation of several Saxon nobles. His half-brother revolted in alliance with other dukes and had Henry captured and arrested when he was just a child. While the half-brother was killed by his own henchmen in 938, Henry, in custody, chose to join the insurgents. He attempted a revolt against his elder brother King Otto in 938, believing he had a claim on the throne as firstborn son after Henry's coronation in 919. In 939, Henry's forces were defeated and he was forced to leave Germany. When Otto's troops invaded Lorraine (Lotharingia) and marched against France, Henry returned and submitted to his elder brother - they were reconciled in 940, and Henry was awarded the Lotharingian duchy. Over the years, the relationship between the brothers improved. He was appointed the Duke of Bavaria in 948. In 951, he accompanied King Otto on his Italian campaign and acted as matchmaker for his brother.
While his brother gained a glorious victory over the Hungarians in the Battle of Lechfeld, Henry fell ill in 955 and died on November 1 in Pohlde Abbey.
Henry married Judith of Bavaria around 950, giving him family ties to Bavaria.