THE TURKISH CONQUEST 237
part of the present kingdom of Servia. Mohammed’s object was to prepare for the struggle with Hungary, the only Power which he seriously feared, for Genoa was now weak, and Venice’s first thought was “ not to recover the bulwark of Christendom from the hands of the Muslim, but to preserve her own commercial privileges under the Infidel ruler.”1 In 1454 the Turks invaded Servia, captured Ostrovica, and besieged Smederevo (Semendria); but John Hunyadi led an army against them, relieved that stronghold, defeated them at Krusevac, and burnt the fortress of Vidin on the Danube. But the following year Mohammed advanced in person and captured Novobrdo,2 with its valuable mines, “Totam religionem Christianam libidinoso ambicio-soque animo dicioni suae ascripsit, flagratque cupidine mundi,” as the Ragusan reports informed the Hungarian king. The Republic suffered ill-effects from this capture, because the Ragusan merchants who had a flourishing trade there were driven out. In July 1456 Mohammed besieged Belgrad, but was defeated by the courage of the defenders aided by the brilliant strategy of Hunyadi. Unfortunately this great leader died soon afterwards, and Hungary was crippled by internal troubles. In 1457 Fra Marino da Siena travelled through Dalmatia to preach a crusade against the Turks and collect money for that purpose. He raised 4000 ducats at Ragusa alone,3 and the King of Hungary requested the Senate to use its influence to induce him to devote the money
1	Prof. Bury in the Cambridge Modern History, i. p. 68.
        2	“ Caput illius patriae et ob mineras belli nervus.”
        3	Dipl. Rag., 347.