Otto I of Brunswick-Lüneburg

Otto I of Brunswick (c. 1247–1279), a Welf and son of Duke Otto the Child, was bishop of Hildesheim from 1260 until his death. Elected while still under age, he was confirmed by the pope in 1264 and consecrated in 1274. He enlarged his church's lands, buying the county of Wohldenberg in 1275.

A feud with his brother Duke Albert followed an arbitration awarding Albert five Salzgau villages. After their brother John, who had supported Otto, died, the war went badly: Albert took Campen and marched on Hildesheim. Otto died with the town under threat on 4 July 1279, aged thirty-two.