William I KG, called the Victorious, a member of the House of Welf, was Duke of Brunswick-Lüneburg. He was reigning Prince of Lüneburg from 1416 to 1428 and of Brunswick-Wolfenbüttel from 1428 to 1432, counted either as William III or William IV. From 1432 he ruled over the newly established Principality of Calenberg, from 1463 also over the Principality of Göttingen. In 1473 he stepped down in favour of his sons, to assume the rule in Brunswick-Wolfenbüttel.

Frederick was the last Burgrave of Nuremberg from 1397 to 1427, Margrave of Brandenburg-Ansbach from 1398, Margrave of Brandenburg-Kulmbach from 1420, and Elector of Brandenburg from 1415 until his death. He became the first member of the House of Hohenzollern to rule the Margraviate of Brandenburg.