In 922 Rudolph II of Burgundy entered Italy to contest the kingship against
Berengar. During a battle near Firenzuola by
Borgo San Donnino, Boniface, who was Rudolph's brother-in-law, attacked Berengar's pursuing forces, who had already defeated Rudolph's army, allowing the fleeing troops to regroup and return to combat, leading to Berengar's defeat. After securing the kingdom of Italy, Rudolph II granted Boniface the duchy of Spoleto. Boniface's wife Waldrada, sister of the king, was described by
Liutprand of Cremona as distinguished for beauty. Their children were Ademar and Villa, the latter later becoming duchess of Tuscany. It is considered that Boniface received the duchy around 923, shortly after Rudolph's establishment as king. ==Dukedom==