to Paolino Pieri the number taken was 1,254. The castle was destroyed, but the war went on, notwithstanding the Pope's efforts to bring about a peace. The Florentines then made a furious attack on the Castle of Rigomagno, and when the scaling ladders broke down they climbed on one another's shoulders and thus won the walls. The capture of this stronghold made them masters of the Ombrone valley.[232] Thereupon (February, 1208) the Siennese were forced to accept peace on very hard terms. By the treaty concluded between the 13th and 20th of October,[233] they were pledged to yield all their possessions at Poggibonsi, to cede Tornano and its tower, to observe the boundaries adjudged by Ogerio, in every direction, and to leave Montepulciano unmolested. The prisoners on either side were exchanged. But this war already betokens the advent of a new period in Florentine history. The conquest of the _contado_ was no longer in question, for the Republic already possessed it in full. With the growing prosperity born of its numerous victories, the city had now to open roads for its vast commerce. It was not only the vagueness of their respective frontiers and the wish to enlarge them that caused Sienna and Florence to be continually at strife; it was their commercial rivalry in the markets of Italy, and especially as regarded the trade with Rome; this near neighbour having become, through the widespread relations of the Church, the principal centre of financial affairs in the civilised world. For some time past it had been the aim of Florence to obtain a monopoly of these affairs, and this was one reason why she had always adhered to the Guelphs. She had had frequent disputes with Arezzo, Volterra, and above all with Sienna, as being the most powerful city on the road to Rome. So the two rivals were perpetually stirred to fresh and fiercer strife. So, too, before long, the irresistible need of Florence for free communication with the sea became the chief cause of her equally long and sanguinary wars with Pisa, the city barring her way to the coast. But as this conflict had not yet begun, the subject will be resumed in due time. In fact, the peace of Sienna was followed by some years of truce with foreign foes, although there was little peace within the city, where the seeds of civil war were already on the point of bursting forth.