Matilda was the Margrave of Tuscany and for a time was the most powerful leader in northern Italy. She acted as an almost independent leader rather than a subject of the Holy Roman Empire, fighting with it over policy and supporting papal authority over imperial in an effort to reform and revitalize the church.
Nora Duff, Matilda of Tuscany
Giovanni Tabacco, New Cambridge Medieval History, Northern and Central Italy in the Eleventh Century
Francis M Gillis, “Matilda, Countess of Tuscany”, The Catholic Historical Review