It has been well observed by Grisar, in his recent biography of Pope Gregory the Great, that the doctrine of two powers to govern the world, one spiritual and the other temporal, each independent within its own limits, is as old as Christianity itself, and based upon the Divine command to "render to Caesar the things that are Caesar's and to God the things that are God's". The earlier popes, such as Gelasius I (494) and Symmachus (506), write emphatically on this theme, which received illustration in the Christian art of the eighth century in a mosaic of the Lateran palace that represented Christ delivering the keys to St. Silvester and the banner to the Emperor Constantine, and St. Peter giving the papal stole to Leo III and the banner to Charlemagne. The latter scene insists on the papal action in the restoration of the Western Empire, which Dante regards as an act of usurpation on the part of Leo. For Dante, pope and emperor are as two suns to shed light upon man's spiritual and temporal paths respectively, Divinely ordained by the infinite goodness of Him from Whom the power of Peter and of Caesar bifurcates as from a point. Thus, throughout the troubled period of the Middle Ages, men inevitably looked to the harmonious alliance of these two powers to renovate the face of the earth, or, when it seemed no longer possible for the two to work in unison, they appealed to one or the other to come forward as the saviour of society. We get the noblest form of these aspirations in the ideal imperialism of Dante's "De Monarchia", on the one hand; and, on the other, in the conception of the ideal pope, the papa angelico of St. Bernard's "De Consideratione" and the "Letters" of St. Catherine of Siena.

This great conception can vaguely be discerned at the back of the nobler phases of the Guelph and Ghibelline contests; but it was soon obscured by considerations and conditions absolutely unideal and material. Two main factors may be said to have produced and kept alive these struggles: the antagonism between the papacy and the empire, each endeavouring to extend its authority into the field of the other; the mutual hostility between a territorial feudal nobility, of military instincts, and of foreign descent, and a commercial and municipal democracy, clinging to the traditions of Roman law, and ever increasing in wealth and power. Since the coronation of Charlemagne (800), the relations of Church and State had been ill defined, full of the seeds of future contentions, which afterwards bore fruit in the prolonged "War of Investitures", begun by Pope Gregory VII and the Emperor Henry IV (1075), and brought to a close by Callistus II and Henry V (1122). Neither the Church nor the Empire was able to make itself politically supreme in Italy. Throughout the eleventh century, the free Italian communes had arisen, owing a nominal allegiance to the Empire as having succeeded to the power of ancient Rome and as being the sole source of law and right, but looking for support, politically as well as spiritually, to the papacy.

The names "Guelph" and "Ghibelline" appear to have originated in Germany, in the rivalry between the house of Welf (Dukes of Bavaria) and the house of Hohenstaufen (Dukes of Swabia), whose ancestral castle was Waiblingen in Franconia. Agnes, daughter of Henry IV and sister of Henry V, married Duke Frederick of Swabia. "Welf" and "Waiblingen" were first used as rallying cries at the battle of Weinsberg (1140), where Frederick's son, Emperor Conrad III (1138-1152), defeated Welf, the brother of the rebellious Duke of Bavaria, Henry the Proud. Conrad's nephew and successor, Frederick I "Barbarossa" (1152-1190), attempted to reassert the imperial authority over the Italian cities, and to exercise supremacy over the papacy itself. He recognized an antipope, Victor, in opposition to the legitimate sovereign pontiff, Alexander III (1159), and destroyed Milan (1162), but was signally defeated by the forces of the Lombard League at the battle of Legnano (1176) and compelled to agree to the peace of Constance (1183), by which the liberties of the Italian communes were secured. The mutual jealousies of the Italian cities themselves, however, prevented the treaty from having permanent results for the independence and unity of the nation. After the death of Frederick's son and successor, Henry VI (1197), a struggle ensued in Germany and in Italy between the rival claimants for the Empire: Henry's brother, Philip of Swabia (d. 1208), and Otho of Bavaria. According to the more probable theory, it was then that the names of the factions were introduced into Italy. "Guelfo" and "Ghibellino" being the Italian forms of "Welf" and "Waiblingen". The princes of the house of Hohenstaufen being the constant opponents of the papacy, "Guelph" and "Ghibelline" were taken to denote adherents of Church and Empire, respectively. The popes having favoured and fostered the growth of the communes, the Guelphs were in the main the republican, commercial, burgher party; the Ghibellines represented the old feudal aristocracy of Italy. For the most part the latter were descended from Teutonic families planted in the peninsula by the Germanic invasions (of the past), and they naturally looked to the emperors as their protectors against the growing power and pretensions of the cities. It is, however, clear that these names were merely adopted to designate parties that, in one form or another, had existed from the end of the eleventh century.

In the endeavour to realize the precise signification of these terms, one must consider the local politics and the special conditions of each individual state and town. Thus, in Florence, a family quarrel between the Buondelmonti and the Amidei, in 1215, led traditionally to the introduction of "Guelph" and "Ghibelline" to mark off the two parties that henceforth kept the city divided; but the factions themselves had virtually existed since the death of the great Countess Mathilda of Tuscany (1115), a hundred years before, had left the republic at liberty to work out its own destinies. The rivalry of city against city was also, in many cases, a more potent inducement for one to declare itself Guelph and another Ghibelline, than any specially papal or imperial proclivities on the part of its citizens. Pavia was Ghibelline, because Milan was Guelph. Florence being the head of the Guelph league in Tuscany, Lucca was Guelph because it needed Florentine protection; Siena was Ghibelline, because it sought the support of the emperor against the Florentines and against the rebellious nobles of its own territory; Pisa was Ghibelline, partly from hostility to Florence, partly from the hope of rivalling with imperial aid the maritime glories of Genoa. In many cities a Guelph faction and a Ghibelline faction alternately got the upper hand, drove out its adversaries, destroyed their houses and confiscated their possessions. Venice, which had aided Alexander III against Frederick I, owed no allegiance to the Western empire, and naturally stood apart.

One of the last acts of Frederick I had been to secure the marriage of his son Henry with Constance, aunt and heiress of William the Good, the last of the Norman kings of Naples and Sicily. The son of this marriage, Frederick II (b. 1194), thus inherited this South Italian kingdom, hitherto a bulwark against the imperial Germanic power in Italy, and was defended in his possession of it against the Emperor Otho by Pope Innocent III, to whose charge he had been left as a ward by his mother. On the death of Otho (1218), Frederick became emperor, and was crowned in Rome by Honorius III (1220). The danger, to the papacy and to Italy alike, of the union of Naples and Sicily (a vassal kingdom of the Holy See) with the empire, was obvious; and Frederick, when elected King of the Romans, had sworn not to unite the southern kingdom with the German crown. His neglect of this pledge, together with the misunderstandings concerning his crusade, speedily brought about a fresh conflict between the Empire and the Church. The prolonged struggle carried on by the successors of Honorius, from Gregory IX to Clement IV, against the last Swabian princes, mingled with the worst excesses of the Italian factions on either side, is the central and most typical phase of the Guelph and Ghibelline story. From 1227, when first excommunicated by Gregory IX, to the end of his life, Frederick had to battle incessantly with the popes, the second Lombard League, and the Guelph pary in general throughout Italy. The Genoese fleet, conveying the French cardinals and prelates to a council summoned at Rome, was destroyed by the Pisans at the battle of Meloria (1241); and Gregory's successor, Innocent IV, was compelled to take refuge in France (1245). The atrocious tyrant, Ezzelino da Romano, raised up a bloody despotism in Verona and Padua; the Guelph nobles were temporarily expelled from Florence; but Frederick's favourite son, King Enzio of Sardinia, was defeated and captured by the Bolognese (1249), and the strenuous opposition of the Italians proved too much for the imperial power. After the death of Frederick (1250), it seemed as if his illegitimate son, Manfred, King of Naples and Sicily (1254-1266), himself practically an Italian, was about to unite all Italy into a Ghibelline, anti-papal monarchy. Although in the north the Ghibelline supremacy was checked by the victory of the Marquis Azzo d'Este over Ezzelino at Cassano on the Adda (1259), in Tuscany even Florence was lost to the Guelph cause by the sanguinary battle of Montaperti (4 Sept., 1260), celebrated in Dante's poem. Urban IV then offered Manfred's crown to Charles of Anjou, the brother of St. Louis of France. Charles came to Italy, and by the great victory of Benevento (26 Feb., 1266), at which Manfred was killed, established a French dynasty upon the throne of Naples and Sicily. The defeat of Frederick's grandson, Conradin, at the battle of Tagliacozzo (1268) followed by his judicial murder at Naples by the command of Charles, marks the end of the struggle and the overthrow of the German imperial power in Italy for two and a half centuries.

Thus the struggle ended in the complete triumph of the Guelphs. Florence, once more free and democratic, had established a special organization within the republic, known as the Parte Guelfa, to maintain Guelph principles and chastise supposed Ghibellines. Siena, hitherto the stronghold of Ghibellinism in Tuscany, became Guelph after the battle of Colle di Valdelsa (1269). The pontificate of the saintly and pacific Gregory X (1271-1276) tended to dissociate the Church from the Guelph party, which now began to look more to the royal house of France. Although they lost Sicily by the "Vespers of Palermo" (1282), the Angevin kings of Naples remained the chief power in Italy, and the natural leaders of the Guelphs, with whose aid they had won their crown. Adherence to Ghibelline principles was still maintained by the republics of Pisa and Arezzo, the Della Scala family at Verona, and a few petty despots here and there in Romagna and elsewhere. No great ideals of any kind were by this time at stake. As Dante declares in the "Paradiso" (canto vi), one party opposed to the imperial eagle the golden lilies, and the other appropriated the eagle to a faction, "so that it is hard to see which sinneth most". The intervention of Boniface VIII in the politics of Tuscany, when the predominant Guelphs of Florence split into two new factions, was the cause of Dante's exile (1301), and drove him for a while into the ranks of the Ghibellines. The next pope, Benedict XI (1303-1304), made earnest attempts to reconcile all parties; but the "Babylonian Captivity" of his successors at Avignon augmented the divisions of Italy. From the death of Frederick II (1250) to the election of Henry VII (1308), the imperial throne was regarded by the Italians as vacant. Henry himself was a chivalrous and high minded idealist, who hated the very names of Guelph and Ghibelline; his expedition to Italy (1310-1313) roused much temporary enthusiasm (reflected in the poetry of Dante and Cino da Pistoia), but he was successfully resisted by King Robert of Naples and the Florentines. After his death, imperial vicars made themselves masters of various cities. Uguccione della Faggiuola (d. 1320), for a brief while lord of Pisa "in marvellous glory", defeated the allied forces of Naples and Florence at the battle of Montecatini (29 Aug., 1315), a famous Guelph overthrow that has left its traces in the popular poetry of the fourteenth century. Can Grande della Scala (d. 1339), Dante's friend and patron, upheld the Ghibelline cause with magnanimity in eastern Lombardy; while Matteo Visconti (d. 1322) established a permanent dynasty in Milan, which became a sort of Ghibelline counterbalance to the power of the Angevin Neapolitans in the south. Castruccio Interminelli (d. 1328), a soldier of fortune who became Duke of Lucca, attempted the like in central Italy; but his signory perished with him. Something of the old Guelph and Ghibelline spirit revived during the struggle between Ludwig of Bavaria and Pope John XXII; Ludwig set up an antipope, and was crowned in Rome by a representative of the Roman people, but his conduct disgusted his own partisans. In the poetry of Fazio degli Uberti (d. after 1368), a new Ghibellinism makes itself heard: Rome declares that Italy can only enjoy peace when united beneath the scepter of one Italian king.

Before the return of the popes from Avignon, "Guelph" and "Ghibelline" had lost all real significance. Men called themselves Guelph or Ghibelline, and even fought furiously under those names, simply because their forbears had adhered to one or other of the factions. In a city which had been officially Guelph in the past, any minority opposed to the government of the day, or obnoxious to the party in power, would be branded as "Ghibelline". Thus, in 1364, we find it enacted by the Republic of Florence that any one who appeals to the pope or his legate or the cardinals shall be declared a Ghibelline. "There are no more wicked nor more mad folk under the vault of heaven than the Guelphs and Ghibellines", says St. Bernardino of Siena in 1427. He gives an appalling picture of the atrocities still perpetuated, even by women, under these names, albeit by that time the primitive signification of the terms had been lost, and declares that the mere professing to belong to either party is in itself a mortal sin. As party catch-words they survived, still attended with bloody consequences, until the coming to Italy of Charles V (1529) finally re-established the imperial power, and opened a new epoch in the relations of pope and emperor.

SISMONDI, Histoire des Republiques italiennes du moyen age; BALBO, Sommario della Storia d'Italia (Florence, 1856); BRYCE, The Holy Roman Empire; TOUT, The Empire and the Papacy (London, 1903); LANZANI, Storia dei communi italiani dalle origini al 1313 (Milan, 1881); SALZER, Ueber die Anfange der Signorie in Oberitalien (Berlin, 1900); BUTLER, The Lombard Communes (London, 1906); CAPPONI, Storia della Repubblica di Firenze (Florence, 1888); VILLARI, I primi due secoli della Storia di Firenze (new ed., Florence, 1905); earlier ed. translated into English by Linda Villari); DOUGLAS, A History of Siena (London, 1902); WIKSTEED AND GARDNER, Dante and Giovanni del Virgilio (London, 1901); RENIER, Liriche edite ed inedite di Fazio degli Uberti (Florence, 1883); SCHOTT, Welfen und Gibelinge in Zeitschrifte f. Geschichtswissenschaft (1846), V, 317; HOLDER-EGGER, Cronica Fratris Salimbene (Hanover, 1905-08).

Edmund G. Gardner.