Брауншвейг-Люнебург
He was the eldest son of the Brunswick duke Albert the Tall and his second wife Adelaide, daughter of Margrave Boniface II of Montferrat. His father had ruled the Duchy of Brunswick-Lüneburg jointly with his brother John, until both divided their territory in 1269. Albert went on to rule the Principality of Wolfenbüttel until his death in 1279.