guelph

Etymology

From Italian guelfo, from Middle High German Welf, a Bavarian dynasty. Welf II, Duke of Bavaria, inherited from his Italian wife, the Countess Matilda of Tuscany, possessions including Tuscany, Ferrara, Modena, Mantua and Reggio, which played a role in the Investiture Controversy. The Welf dynasty sided with the Pope in this controversy, so partisans of the Pope became known in Italy as Guelfi.