Word Origin & History
1579, from It. Guelfo, from O.H.G. Welf, name of a princely family that became the ducal house of Brunswick, lit. "whelp," originally the name of the founder. One of the two great parties in medieval It. politics, characterized by support of the popes against the emperors (opposed to the Ghibellines).
They are the ancestors of the present dynasty of Great Britain. The name is said to have been used as a war-cry at the Battle of Weinsberg (1140) by partisans of Henry the Lion, duke of Bavaria, who was of the family, against Emperor Conrad III; hence it was adopted in Italy as the name of the anti-imperial party.