On June 29, the army of the Count of Armagnac, with 3,000 infantry and 7,500 cavalry, after crossing Montferrat, he faced the plain in front of Alessandris and laid siege to the village of Castellazzo Bormida, defended, perhaps, by the inhabitants alone.

[2] On July 25 Jacopo dal Verme (who in the meantime had arrived in Alexandria with about 4,000 infantry, partly crossbowmen and partly pikemen, and 6,000 cavalry) sent a hundred horsemen to scout nearby of the enemy camp, the action annoyed Armagnac to such an extent that, after listening to mass and drinking a cup of wine, he decided to answer to the provocation of the viscounts by leading 1,500 knights in pursuit of enemy knights.

So, Jacopo dal Verme, who with his men had come out of Porta Genovese (a city gate) seeing that there fear was taking hold of his troops he also dismounted and was immediately imitated by his knights.

After the scouts informed him that there were no other enemy formations behind the 1,500 French cavalry gathered around the count of Armagnac, Jacopo dal Verme divided the reserves into three corps: the first, under the command of Broglia da Trino and Brandolino da Bagnocavallo moved by Bergoglio (a suburb of Alessandria), while at the same time, Calcino Tornielli, from Porta Marengo, would have struck the enemies on the flank and, inside the walls, other units would have been gathered ready to tuck in the men of dal Verme deployed outside the Porta Genovese.

Probably satisfied with the victory obtained, Jacopo dal Verme did not push his men towards the enemy camp, where most of Armagnac's forces were still located, and preferred to return to the city to reorganize his army.

We do not know how bloody the fight was, however, as reported by the ambassadors of Siena, the Visconti army defeated the French again and many knights of the Count of Armagnac surrendered to Jacopo dal Verme.