Dhameystir weedha soo socota: William wuxuu ahaa wiilkii ugu weynaa ee Duke Brunswick Henry the Mild oo ka dhashay guurtiisii ugu horreysay Sophia, oo ahayd gabadhii Duke Griffin Wartislaw IV ee Pomerania. Markii uu aabihii geeriyooday sanadkii 1416, wuxuu dhaxlay Boqortooyada Brunswick ee Lüneburg oo uu si wada jir ah ula xukumay walaalkiis ka yar Henry the Peaceful. William waxa uu noqday taliye firfircoon; wax yar ka dib wuxuu galay khilaafyo badan oo la lahaa amiirada deriska ah sida Archbishop of Bremen iyo Bishop of Hildesheim, wuxuuna taageeray Counts of Schauenburg iyo Holstein dagaalka ay kula jiraan Boqor Eric ee Denmark. Wuxuu sidoo kale la dagaalamay Margrave Frederick oo reer Meissen ah isagoo ka adkaaday
Ciidamada Hussite ee 1421 Dagaalkii Brüx.