He and his descendants were on and off dukes of Spoleto, commonly in opposition to the Guideschi clan, another Frankish family powerful in central Italy.
The family consolidated its holdings in northern Italy through the 820s, 830s, and 840s, often controlling the counties of Brescia (hereditarily), Parma, Cremona, and Piacenza among others.
They shared power with the bishops in the cities and were stoutly loyal to the emperors in order to ensure the peace and stability necessary to rule their vast and separated domains in the Po valley.
With her influence, the Supponids became the most powerful noble family in Italy during the two decades of Louis's reign and one of the few to hold high offices.
During the tenth century another Supponid daughter, Hildegard, married Adalbert-Atto of Canossa and they were the paternal great-grandparents of Matilda of Tuscany, who became one of the most important governing figures of the Italian Middle Ages.