These successes were not unproductive of results. For when the Florentines next attacked Pistoia in 1253, the town surrendered after a brief resistance, and agreed (February 1, 1254) to forsake the Ghibelline League, to grant readmittance to the Guelphs, and to be entirely at the service of Florence.[255] Thereupon the Florentines hastened to defend Montalcino against another attack by the Siennese; and thus the war with the latter, begun at the end of 1253, was vigorously pursued in 1254, to the month of June. Then, having lost many strongholds--some captured by Florentine arms, others gained by purchase from the Counts Guidi--Sienna was forced to end the war and tender submission. On their way back to Florence the victors reduced Poggibonsi, a large and important territory adhering to Sienna and the Ghibellines. They next proceeded to devastate the lands about Volterra, although the city itself seemed impregnable from the strength of its position. But when the Volterrani, counting upon this, ventured to sally forth and give battle, they were defeated and pursued with so much vigour, that the Florentines found themselves inside the city before they had even conceived the possibility of storming its walls. There was such general alarm among the inhabitants that a great throng of old men, women, and children, with the bishop at their head, came as suppliants to make surrender. The Florentines showed much generosity, prohibiting pillage, and merely reforming the government of the city by transferring it to the Guelphs. And now Pisa, being bereft of all allies, finally agreed to surrender, and the terms were subscribed on August 4, 1254. As a result of this treaty the Florentines had right of passage through Pisa, with their merchandise, and exemption from all taxes, dues, or imposts, whether by sea or by land. Moreover, in all contracts made with them, the Pisans were bound to employ Florentine weights and measures, and also, to some extent, Florentine money. They yielded several districts and castles, that of Ripafratta included. And they were compelled to give 150 hostages to secure their observance of these conditions and of the friendship to which they were sworn. Shortly after this event Arezzo likewise made submission (25th of August), and accepted a Podestà from Florence.[256]