A new danger now threatened Siena and Pandolfo alike. Cesare Borgia, with the aid of his father, Pope Alexander VI., was building up a great state for himself in central Italy. He had conquered the Romagna, added Piombino to his dominions in September 1501, and was casting eyes upon Siena. In the spring of 1502 the Pope invited Pandolfo to meet him at Piombino; but the Magnifico, pleading excuses and delays, did not go. In August Pandolfo purchased the protection of King Louis XII. of France, with the moneys of the Republic. He sent ambassadors to congratulate Cesare on his conquests, but plotted against him with the petty tyrants who led his mercenaries and began to suspect that their own turns were coming. In the autumn took place the famous meeting of the conspirators at La Magione, to ally against Cesare--"for the salvation of all, and not to be, one by one, devoured by the dragon," as their leading spirit, Giampaolo Baglioni of Perugia, put it. Pandolfo was represented by Antonio da Venafro and Guido Pecci, and hoped for Piombino as his share of the spoils. At the same time he tried to treat with the Borgia, using Antonio da Venafro as a go-between. "This man," said Cesare to Machiavelli (who was with him as ambassador of Florence), "sends me every day either letters or special envoys to make me understand his great friendship towards me, but I know him." It is needless to repeat the tale here of how Cesare--when his forces were temporarily defeated at Fossombrone--waited until the time was ripe, and then crushed the wretched conspirators at the famous _tradimento_ of Sinigaglia. Pandolfo had kept out of the trap. Perugia surrendered on January 6th, 1503; Giampaolo Baglioni fled with his followers to join his Sienese ally.