or Guelfs, a celebrated faction in Italy, antagonists of the Ghibelins. See Ghibelins.

The Guelphs and Ghibelins filled Italy with blood and carnage for many years. The Guelphs stood for the pope, against the emperor; the Ghibelins for the emperor against the pope. The rise of the Guelphs is referred by some to the time of Conrad III. in the twelfth century; by others to that of Frederick II.; and by others, again, to that of his successor Frederick II. in the thirteenth century. The name of Guelph is commonly said to have been formed from Wolfe, or Welfo. The Emperor Conrad III., having taken the duchy of Bavaria from Welf VI., brother of Henry duke of Bavaria, Welfe, assisted by the forces of Roger king of Sicily, made war on Conrad, and thus gave birth to the faction of the Guelphs. But some derive the name Guelph from the German Wolf, on account of the grievous evils committed by that cruel faction; and others deduce it from the name of a German called Guelph, who lived at Pistoye, adding, that his brother, named Gibel or Ghibel, gave his name to the Ghibelins.