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.

The Hussite Wars, also called the Bohemian Wars or the Hussite Revolution, were a series of civil wars fought between the Hussites and the combined Catholic forces of Holy Roman Emperor Sigismund, the Papacy, and European monarchs loyal to the Catholic Church, as well as various Hussite factions. At a late stage of the conflict, the Utraquists changed sides in 1432 to fight alongside Roman Catholics and opposed the Taborites and other Hussite spin-offs. These wars lasted from 1419 to approximately 1434.