In Eastern Europe[352] the Inquisition never succeeded in obtaining much of a foothold. The main stronghold of Catharism was in lands east of the Adriatic, but here the papacy possessed but scant authority. A practically abortive attempt was made to deal with the heretics in 1202; but in the twenties the Mendicants in their untiring zeal, using Hungary as their base and with the armed support of Calomar, Duke of Croatia and Dalmatia, waged successful warfare against the Bosnian Cathari until the retirement of the crusaders in 1239. Their withdrawal meant that no effectual result was achieved, and Catharism remained powerful not only in Bosnia, but Dalmatia, Bulgaria, and Roumania. The bishops of Bosnia found themselves compelled to leave the country. In 1298 an attempt made by Boniface VIII, to establish an Inquisition in the lands south of Hungary from the Danube to Macedonia, came to nothing. But in 1320 an inquisitor named Fabiano, with the assistance of the king of Hungary, made some progress against the heretics, and a further effort was made in 1336 by Dominicans with the co-operation of the Hungarian king. Though in 1378 Urban V congratulated Louis of Hungary and the friars on having restored two thousand heretics to the fold, four years later that monarch himself complains that practically all his subjects are Cathari, good Catholics being very sparse in numbers. In 1407 Sigismund made an attempt to establish himself in Bosnia, his cause obtaining papal recognition as a crusade against Turks and Manichæans; but his attempt ended in failure. In 1432 an Observative Franciscan, Giacomo della Marca, already well known as a stalwart persecutor of heretics in Italy, embarked upon a missionary enterprise in Slavonia, and is said by his eloquence to have made numerous converts; but his success was short-lived, as he was recalled by Sigismund to help in the religious troubles of Bohemia. After the days of Sigismund there was little chance of success for missionary or inquisitor beyond the Adriatic. The flow of the Ottoman advance swept over the Balkans, and the Cathari were converted not to Catholicism but to the faith of Islam.