Meanwhile Charles continued his aggressive policy with regard to the Ghibellines, and was seconded by the Florentines, who marched out under the banner of the Commune, sometimes alone, but oftener in junction with the French cavalry, to impose peace and assure the triumph of their party in all the neighbouring towns. But their arrogant daring was sometimes pushed too far. When the Ghibellines were expelled from Bölogna, the Florentines immediately set out to proffer their unrequested aid to that city. But, much to their amazement, on reaching the banks of the Reno, they found the Bölognese waiting to drive them back. The latter had achieved their purpose of banishing the Ghibellines, but had no intention of allowing the haughty Florentines to come to disseminate their own party rancours under pretence of assisting the city. The Podestà of the Florentines was killed in trying to push through the opposing force, and the humiliated expedition had to retrace its steps (1274). They were more fortunate with regard to Pisa. That city, being torn by party strife, had banished Giovanni Visconti, judge of Gallura, and Count Ugolino della Gherardesca di Donoratico, two ambitious Ghibelline nobles, who, deserting their own for the Guelph cause, applied to the Florentines for help. They immediately granted it, and joining forces with their new friends and the French, invaded the territories of their old rival, capturing the Castle of Asciano in September, 1275. The following June, at the instigation of the same exiled nobles, they resumed hostilities with a larger army, aided by the Lucchese and other Guelphs, and accompanied by the king's marshal. Again victorious, they compelled Pisa to make peace on June 13, 1276, and recall her exiles, especially the Count Ugolino, whose ambition was destined to bring fatal consequences on himself and his native town.