The new king recognized that his only hope lay in obtaining aid from Christendom, to earn which he labored energetically to strengthen the Catholic Church in his dominions, but, in the fatal perverseness of the time, this only precipitated his downfall. From Pius II. he obtained only barren instructions to the legate, Lorenzo, Abbot of Spalatro, to collect money and crusaders. From Matthias Corvinus he purchased an alliance by a heavy payment, by surrendering some castles, and by breaking off relations with the Turks and ceasing to pay them tribute. In all this he estranged still further his heretic subjects and drew upon his head the vengeance of Mahomet II. Many Cathari, driven from Bosnia, had found refuge in Moslem territory; others, especially nobles, forced to pretend conversion, maintained constant relations with the Turks, kept them advised of all that occurred, and were eager to aid them, in hopes of revenge. The news of the treaty with Matthias Corvinus was speedily conveyed to Mahomet, who, to test its truth, sent an envoy to demand the tribute. King Stephen took him to the treasury, showed him the money, and refused to deliver it, saying that he needed it for self-defence, or that it would support him in exile if driven from the kingdom, and he paid no heed to the envoy’s warning that treasure withheld in defiance of pledges would bring him no luck.[351]
Defiance such as this left nothing to hope for from the Turk, but preoccupations in Wallachia kept Mahomet busy during 1462, and he postponed his revenge till the following year. It shows the blindness of Rome to the situation and the unflagging persistency of the determination to secure uniformity of faith, that during this respite Pius II. sent learned friars to Bosnia with instructions that the best mode of overcoming heresy was to promote study. The instructions were excellent, but sadly misplaced. Through the winter and spring of 1463 Mahomet was preparing the final blow by massing one hundred and fifty thousand men at Adrianople. To throw Stephen Thomasevic off of his guard, his request for a fifteen years’ truce was granted, and his envoys, returning with this welcome news, were followed, after an interval of four days, by the Turkish host. The land was found defenceless, and no resistance was offered till the invaders reached the royal castle of Bobovac, a stronghold capable of prolonged defence. Its commandant, however, was Count Radak, a Catharan who had been forced to conversion, and on the third day he surrendered on a promise of reward. When he claimed this, Mahomet, reproaching him with his treason, had him promptly beheaded, and tradition still points out on the road to Sutiska the rock Radakovica, where the traitor met his end. The capitulation of Bobovac cast terror throughout the land. Resistance was no longer thought of, and the only alternatives were flight or submission. The king hurried towards the Croatian frontier, with Mahomet Pasha at his heels, and was compelled at Kljuć to surrender on promise of life and freedom, but, in spite of this, he was put to death, after being utilized to order all commandants of cities and castles to surrender them. Within eight days more than seventy towns fell into the hands of the Turks, and by the middle of June all Bosnia was in their possession. Then Mahomet turned southward to overrun the territories of Stephen Vukcić, but the mountains of Herzegovina were bravely defended by the Cathari, and by the end of June the Turkish host took its way homeward, carrying with it one hundred thousand prisoners and thirty thousand youths to be converted into Janissaries.[352]