Ghibellinism united the princes in an opposite camp.

'The Guelf party,' writes Giovanni Villani, 'forms the solid and unalterable basis of Italian liberty, and is so antagonistic to all tyranny that, if a Guelf become a tyrant, he must of necessity become at the same moment Ghibelline.' Milan, first to assert the rights of the free burghs, was now the chief center of despotism; and the events of the next century resume themselves in the long struggle between Florence and the Visconti.

The chronicle of the Villani and the Florentine history of Poggio contain the record of this strife, which seemed to them the all-important crisis of Italian affairs.

In the Milanese annals of Galvano Fiamma and Mussi, on the other hand, the advantages of a despotic sovereignty in giving national coherence, the crimes of the Papacy, which promoted anarchy in its ill-governed States, and the prospect of a comprehensive Italian tyranny under the great house of the Visconti, are eloquently pleaded.

The terms of the main issue being thus clearly defined, we may regard the warfare carried on by Bertrand du Poiet and Louis of Bavaria in the interests of Church and Empire, the splendid campaigns of Egidio d'Albornoz, and the delirious cruelty of Robert of Geneva, no less than the predatory excursions of Charles IV., as episodical.