How did the Guelfs and Ghibellines differ in medieval Italian politics?

In medieval Italian politics, the Guelfs and Ghibellines were opposing factions whose rivalry centered on the struggle for power between the papacy and the Holy Roman Empire.1

• Guelfs: Generally supported the authority of the pope and opposed imperial interference in Italian affairs. In cities like Florence, the party often represented wealthy merchant interests.1
• Ghibellines: Sympathized with the German emperors and sought to maintain or restore imperial influence in Italy. This faction was frequently associated with feudal aristocrats who favored the emperor's prerogatives.1

The conflict, which intensified during the 13th and 14th centuries, often exacerbated local tensions within Italian communes, leading to frequent exiles and civil strife. While the rivalry originated from German dynastic disputes, it became deeply embedded in Italian city-state politics. By the time of Dante Alighieri, the political landscape had shifted further; in Florence, the Guelf party itself fractured into "Blacks" and "Whites," a division that ultimately led to Dante’s political exile.12