Now, however, the state of affairs was about to take a fresh turn. In consequence of Conrad's decease, Manfred, the other son of Frederic II., succeeded to the Neapolitan throne. The new sovereign, being dauntless, ambitious, and full of talent, devoted all his powers to forwarding the interests of the Italian Ghibellines; and the Florentines, with their usual shrewdness, immediately became more cautious in their proceedings. In 1255 they made alliance with Sienna, the following year with Arezzo, severely blamed their captain, Count Guido Guerra, for expelling the Ghibellines from the latter city, and compelled him to recall them. They even treated their own exiles with greater indulgence and liberality, permitting some of them to return from time to time. But on either side these were false demonstrations, leading to no result. All were temporising, waiting to see what fresh turn the general affairs of Italy might take. Supposing Manfred's fortunes to be really restored, the Florentines would suffer severely, and of this they were perfectly aware. A first warning was received by them in 1256, when the Pisans, oblivious of sworn terms and promises, made an attack upon Ponte a Serchio, a castle held by the Lucchese, the allies of Florence. Accordingly the Florentines hastened to their friends' relief, and routed the assailants, many of whom were drowned in the river in their flight. After this victory the troops marched towards Pisa and coined money in sight of the walls, an act then considered to inflict deep humiliation on the enemy. In addition to this the Pisans were not only forced to renew (September 23, 1256) the ignominious peace concluded in 1254, but also to cede many castles to the Florentines, and some few to the Lucchese.[262] And another clause was added to the terms stipulating that the Castle of Mutrone, a position of great strategical importance both to Lucchese and Florentines, should be given up to the latter, with power to destroy or preserve it, as their magistrates might decide. Accordingly the question was discussed by a council of elders in Florence, and one of the number, Aldobrandino Ottobuoni, who, although poor and plebeian, had much influence as a patriot, asserted the necessity of demolishing the fortress. His proposal was carried, but with the proviso that it should be first submitted to the approval of the parliament. Meanwhile the Pisans, unaware of the result of the discussion and of Ottobuoni's amendment, but knowing that the castle, if held by the Lucchese, would be a serious menace to themselves, sent to offer Ottobuoni four thousand florins--in those days a prodigious sum--if he would address the council in favour of the very plan he had already pleaded with success. But this offer merely opened his eyes to the blunder he had committed, and returning to the council, he induced the elders to reverse their decision. Aldobrandino's reputation was so