Leszek II the Black
Upon the death of Leszek II the Black in Poland, Wenceslaus had claimed the throne. Although, this was a controversial move and caused civil war. A substantial amount of Polish nobles and citizens wished for Władysław I the Elbow-high to become King of Poland. Wenceslaus needed help to keep Poland so he decided to marry Kunigunde off to Boleslaus which would create a firm alliance with a powerful Polish noble.