Otto II, Duke of Brunswick-Göttingen

His father left him a financially and ruined politically country. Otto managed to restore political order, but was not able to resolve the financial problems.

In order to restore political order, he allied himself, unlike his father, with to the cities in the region and against the powerful robber barons. He succeeded in 1407, together with the City of Göttingen 1407, to storm the castle at Jühnde, and he also forced the Lords of Adelebsen, Hardenberg and Schwicheldt to respect the peace.

Due to financial constraints he had to borrow money repeatedly from his cousins in Brunswick and in exchange promised them the succession in Göttingen already in 1395. As early as 1435, Otto withdrew from the business of government and gave the Estates a free rein.

The Dukes of Brunswick-Wolfenbüttel, William and Henry, who had shared Brunswick-Wolfenbüttel until 1432, decided to divide their principality, due to the increasing number of disputes between the two of them. They also divided the castles Otto had given them as colleteral for his many loans. A dispute arose between Henry and William about the sovereignty in Göttingen. Otto returned from retirement and sided with Henry against William. In 1441, he occupied the castle at Münden. In 1442, the dispute was settled. Otto retained the city and castle of Uslar, his wife received Münden, Dransfeld and Sichelstein. Seesen and Gandersheim were separated from Brunswick-Göttingen and attached to Henry's part of Brunswick-Wolfenbüttel. William receive the concession from Henry and the Dukes of Lüneburg that he could rule Brunswick-Göttingen until Otto's death.

Probably around 1408, Otto married Agnes (d. 16 January 1471), the daughter of Landgrave Hermann II of Hesse. He had been engaged to her sister Elizabeth, but she died before the wedding. Otto and Agnes had two daughters: Elizabeth, who died young, and Margaret, who married Duke Henry of Schleswig in 1425.

Since he had no male heir, the Brunswick-Göttingen line of the House of Guelph died out when he died in 1463. The Principality of Göttingen fell to Brunswick-Calenberg, which was sometimes called Brunswick-Calenberg-Göttingen afterwards.