Principality of Calenberg
In 1428 there was a further division of the Welf estate between the 2 brothers and their uncle, Bernard, Prince of Brunswick. The brothers William and Henry received the land between the Deister and the Leine, which was later to become the Principality of Brunswick-Wolfenbüttel, having acquired the Principality of Calenberg; and their uncle, Bernard, received the Principality of Lüneburg, thus becoming the progenitor of the Middle House of Lüneburg.