Principality of Lüneburg
Bernard was the second son of Magnus II, Duke of Brunswick-Luneburg. After the death of his father in 1373, he and his brothers agreed with the Ascanian dukes of Saxony-Wittenberg to alternate rule in the Principality of Lüneburg. From 1375 on, Bernard took part in the government de jure, and from 1385 on de facto.