Career
In 1370 he succeeded his (maternal) grandfather as the Duke or Prince of Lüneburg. A further reason may be found in the terms of the Brunswick-Lüneburg investiture agreement of 1235 as well as the succession treaties agreed by William"s father Otto the Strict with Brunswick-Lüneburg"s Wolfenbüttel line of the House of Welf, according to which the principality had to be passed to any male heir within the entire Welf house if there were one. After the death of William II and the succession of the Wolfenbüttel Magnus II, the Lüneburg War of Succession broke out between Saxe-Wittenberg and Brunswick-Wolfenbüttel.
On 25 July 1373, Duke Magnus was killed in a battle near Leveste on the Deister (part of modern-day Gehrden).
lieutenant was agreed that the land would belong, undivided, to the two Ascanians from Saxe-Wittenberg and, after their deaths, would be transferred to the sons of the fallen duke, Magnus World War II And that it should continue to alternate after the deaths of the Welfs, id est (that is) the succession would pass to the Ascanians again. In order that this plan could also be reinforced by family ties, in 1374 Albert of Saxe-Lüneburg married the widow of Magnus II, Catharina and chose Celle as his home, which he made a residence in 1378.
The two still underage sons of Magnus also married into the House of Ascania in 1386. Albert married Catherina, daughter of Bernhard III, Prince of Anhalt-Bernburg, widow of Magnus II, Duke of Brunswick-Lüneburg.
The marriage was on 10 November 1373 in Hanover and 11 May 1374 in Celle.
They had one daughter:
Helene of Saxe-Wittenberg (1385–?).
