Thomas II of Savoy invaded the territory of Asti, but he was defeated[1] by the Astigiani army at Montebruno in Garzigliana, near Pinerolo.

As the commune, however, had begun to erode the lands of the bishop and other local feudatories, the latter sued for help to Frederick Barbarossa, who appeared under the city walls with a huge army in February 1155.

The 13th century saw the peak of the Astigiani economic and cultural splendour, only momentarily hindered by the wars against Alba, Alessandria, Savoy, Milan (which besieged the city in 1230), and the Marquess of Montferrat and Saluzzo.

In this period, the rise of the Casane Astigiane resulted in contrasting political familial alliances of Guelph and Ghibelline supporters.

This later led to intervention by Charles I of Naples, then the most powerful man in Italy thanks to his possessions in Piedmont and Provence alongside his Neapolitan kingdom.