For example, they succeeded in expanding their estate in the area of Gifhorn considerably through the acquisition of the village of Fallersleben and the counties of Papenheim and Wettmarshagen.
Following the death of his brother, Otto III, William increasingly turned his attention to the question of succession in the state of Lüneburg.
In fact he had previously asked Emperor Charles IV for the eventual enfeoffment of the state to his grandson, but backed away again in the years that followed, because he feared the influence of Albert's uncles, Wenceslas and Rudolf.
Unaware of this, Emperor Charles IV had meanwhile authorised the enfeoffment of Albert of Saxe-Wittenberg and his two uncles and, with that, laid the foundation stone for the Lüneburg War of Succession that began on William's death.
In response to William's refusal to pay this, an imperial ban was imposed at first and, after a further vain attempt at mediation, the Emperor pronounced that he should be made an outlaw and tasked the Bishop of Minden to carry this out personally.