Matilda of Tuscany
Welf II, Duke of Bavaria married Countess Matilda of Tuscany, who died childless and left him her possessions, including Tuscany, Ferrara, Modena, Mantua, and Reggio, which played a role in the Investiture Controversy. Since the Welf dynasty sided with the Pope in this controversy, partisans of the Pope came to be known in Italy as Guelphs ("Guelfi").