Hostilities between the two republics had already begun: the colours of Manfred had been dragged with contempt through the streets by the Florentines. Farinata resolved to take advantage of the irritation of the Germans, in order to bring the two parties to a general battle. He knew that some ignorant artisans had found their way into the signoria of Florence, and he tried to profit by their presumption. He flattered them with the hope that he would open to them one of the gates of Siena, if they ordered their army to present itself under the walls of that city. At the same time, his emissaries undertook to excite the ill will of the plebeians against the nobles of the Guelf party, who, being more clear-sighted, might discover his intrigues. Notwithstanding the opposition of the nobles in council, the signoria resolved to march a Guelf army through the territory of Siena.[b] It is said[11] there were not less than thirty thousand, and auxiliary troops came from all the allied cities, or those subjected to the Florentines; but as the Ghibellines had been expelled from these cities, the latter had united at Siena and the Guelfs at Florence, and the two armies presented the sad spectacle of division and civil war in the whole of Tuscany. From Arezzo alone it is asserted that nearly five thousand came to the succour of the Florentines under the command of Donatello Tarlati, whilst another band of outlaws, conducted by their bishop, had joined in Siena, and if we are to believe Raffaello Roncioni, a chosen body of three thousand Pisans also came to Siena. The army of the Guelfs was superior in number to the Ghibellines, that faction being predominant in Tuscany, but probably there was not that disproportion which some historians wish to make us believe. The army of the Guelfs marched on as to certain victory, hoping to enter Siena without fighting; arrived upon the hills of Montaperti they halted to receive advice from the Sienese to proceed further. Nothing is more capable of disconcerting a leader and an army than to see an enemy courageously advancing to meet them, whom they had believed either beaten or fugitive; thus the Florentine generals, who went to the certain conquest of Siena, when they perceived the enemy advancing boldly, at the head of whom was the German troop, so formidable an enemy to them, began to despair. They came to blows, and both sides fought with great valour; but the Florentines, unable to resist the attack made upon them by the Germans, gave way. Treachery aided to increase the consternation. Many Ghibellines, hidden in time of the battle, went over to the enemy. Among the rest, Bocca of the Abati, before going over to the other side, aimed a treacherous blow at Jacopo Vacca, of the family of the Pazzi, who carried the ensign of the republic, and brought him to the ground with the loss of an arm.