Guelphs and Ghibellines, the names of two great parties, the conflict between which may be said almost to epitomise the history of Italy and Germany from the 11th to the 14th century. The origin of these names was formerly the subject of much speculation; but historians are now agreed in tracing them respectively to the two families, Welf and Waiblingen, which in the 12th century were at the head of two rival parties in the German empire, and whose feuds came to be identified historically with the respective principles for which these parties contended. Welf was the personal name of a prehistoric founder of the family still represented in the royal English and (dispossessed) Hanoverian houses; Waiblingen, a small town in Württemberg, was a possession of the House of Hohenstaufen. The assumption of the names as party names is traditionally fixed at the battle of Weinsberg, in Swabia, 1140, between the Emperor Conrad of Hohenstaufen (Duke of Franconia) and Welf, uncle of Henry the Lion, Duke of Saxony, when the leaders rallied their followers by the respective warcries, 'Hie Waiblingen!' 'Hie Welf!' It may be mentioned that Matthew Villani ingeniously gives as etymology of Ghibellini, Guida belli or guidatori di battaglia, 'leaders in battles;' of Guelfi, guardatori di fe, 'defenders of the faith.'
As the chief theatre of the conflict of these parties was Italy, the original names took the Italian forms of Ghibellini and Guelfi. The former may, in general, be described as the supporters of the imperial authority in Italy, the latter as the opponents of the emperors. The opposition to imperial authority in Italy arose from two distinct parties, which, for the most part, made common cause with each other—from the church, which asserted its own spiritual independence, and from the minor principalities and free cities, which fought for their provincial or municipal rights and liberties. Five great crises in the strife of the Guelph and Ghibelline parties are commonly noted by historians: under Henry IV., in 1055; under Henry the Proud of Bavaria and Saxony, in 1127; under Henry the Lion, in 1146; under Frederick Barbarossa, in 1159; and in the pontificate of the great champion of churchmanship, Innocent III. The cities of northern Italy were divided between the two parties—Florence, Bologna, Milan, Piacenza, Modena, Ravenna, and others, as a general rule, taking the side of the Guelphs; while Pisa, Lucca, and Arezzo were Ghibelline. Several important cities transferred their sympathies from the one party to the other according to the exigencies of domestic politics. The great Italian families, in like manner, took opposite sides; but the policy of each family frequently varied from one generation to another. In general, it may be said that the nobles of the more northern provinces of Italy inclined to the Ghibelline side, while those of the central and southern provinces were Guelph. By degrees, however, especially after the downfall of the preponderance of the German emperors in Italy, the contest ceased to be a strife of principles, and degenerated into a mere struggle of rival factions, who availed themselves of the prestige of ancient names and traditional or hereditary prejudices. Even in 1272 Gregory X. could with truth reproach the Italians with their sanguinary animosities for the sake of what were but names, the meaning of which few of them could understand or explain; and, in the following century, in 1334, Benedict XII. practically disallowed altogether the reality of the grounds of division between the parties, by proscribing, under pain of the censures of the church, the further use of those once-stirring names, which had long been the rallying words of a pitiless warfare. From the 14th century we read little more of Guelphs or Ghibellines as actually existing parties; but in the sense already explained the conflict of principles which they represent is found in every period of history. See Bryce, The Holy Roman Empire (9th ed. 1888); Oscar Browning, Guelphs and Ghibellines (1893).
The reigning family of Great Britain occupy the throne in virtue of the Act of Settlement of 1701, which made Sophia, daughter of Frederick, elector Palatine, and of Elizabeth, daughter of James I. of England, heiress of the English crown. Sophia married Ernest Augustus, Duke of Hanover, the fourth son of George, Duke of Brunswick-Lüneburg, a direct descendant of the prince of Guelph blood in whose favour Frederick II. created the duchy of Brunswick-Lüneburg in 1235. See HANOVER.