Guelphs and Ghibellines

The names were likely introduced to Italy during the reign of Frederick Barbarossa. When Frederick conducted military campaigns in Italy to expand imperial power there, his supporters became known as Ghibellines (Ghibellini). The Lombard League and its allies were defending the liberties of the urban communes against the Emperor's encroachments and became known as Guelphs (Guelfi) or "church party".

A 14th Century conflict between the militias of the Guelph and Ghibelline factions in the comune of Bologna, from the Croniche of Giovanni Sercambi of Lucca

The Ghibellines were thus the imperial party, while the Guelphs supported the Pope. Broadly speaking, Guelphs tended to come from wealthy mercantile families, whereas Ghibellines were predominantly those whose wealth was based on agricultural estates. Guelph cities tended to be in areas where the Emperor was more of a threat to local interests than the Pope, and Ghibelline cities tended to be in areas where the enlargement of the Papal States was the more immediate threat.

During the 12th and 13th centuries, armies of the Ghibelline communes usually adopted the war banner of the Holy Roman Empire—white cross on a red field—as their own. Guelph armies usually reversed the colors—red cross on white. These two schemes are prevalent in the civic heraldry of northern Italian towns and remain a revealing indicator of their past factional leanings. Traditionally Ghibelline towns like Pavia, Novara, Como, Treviso and Asti, continue to sport the Ghibelline cross.

 The Guelph cross can be found on the civic arms of traditionally Guelph towns like Milan, Vercelli, Alessandria, Padua, Reggio and Bologna.

Some individuals and families indicated their faction affiliation in their coats of arms by including an appropriate chief: Guelphs had a capo d'Angio or "chief of Anjou", gold fleurs-de-lys on a blue field, with a red heraldic "label", while Ghibellines had a capo dell'impero or "chief of the empire", with a form of the black German imperial eagle on a gold background.

In the course of the Italian Wars of 1494 to 1559, the political landscape changed so much that the former division between Guelphs and Ghibellines became obsolete. This is evident with the election of Pope Paul V (1605), the first pope to bear the "Ghibelline" imperial eagle in chief of his coat of arms.