Bosnia, which had borne its part in the fatal battle of Kosovo field (1389), was inevitably drawn into the vortex. The catastrophe of this land received a peculiar character from its religious condition. The mass of the people, high and low, was firmly devoted to the Patarine or Bogomilian tenets, which Catholics and Greeks branded as Manichaeanism. It is one of that series of religions which range from Armenia to Aquitaine, including Albigensians at one extremity and Paulicians at the other, all apparently descended from the ancient “heresies” of Adoptianism. But the Catholics were eager to crush the heresy; Franciscan missionaries worked with all their might in the land; and some of the kings embraced Catholicism. In 1412 the Bogomils threatened to Turcise, and in 1415 they executed the threat, fighting at Usora against Hungary. When King Stephen Thomas embraced Catholicism (1446), the Pope and the King of Hungary hoped that the false doctrines would be extirpated. In the south of the Bosnian kingdom was the large vassal state, practically independent, which had grown up out of the lordship of Chlum. The voivod of this country was Stephen Vukcic, and in 1448 he received from the Emperor the title of “Duke (Herzog) of St Sabas”; whence the complex of his lands derived the name of Herzegovina, the Duchy. His daughter married Stephen the King; but Stephen the Duke remained true to the national faith. He seems to have entered into a sort of vassal relation to Mohammad; for, when he makes peace with his neighbour Ragusa in 1454, we find him undertaking not to attack it, save at the command of the “Great ruler the Sultan of Turkey.” On the fall of Constantinople the Bosnian King offered tribute; but Hunyady’s feat at Belgrade, and the success of Scanderbeg in the south, raised up King Stephen’s drooping hopes and heartened him to refuse the payment (1456). Before, however, any results ensued from his change of attitude, he made peace again (1458); his object was to have his hands free for laying hold of Servia. In the diet of Szegedin the Hungarian King agreed that the despot’s son, Stephen Tomasevic, should become despot of Servia and actual ruler of the little northern strip of Servia that was not in Turkish power. The position here depended entirely on holding the key-fortress of Semendra. But the inhabitants of this place were reluctant to submit to the Bosnian prince imposed upon them; and when in the next year Mohammad appeared with an army, they opened their gates to him. A cry of mortification at the fall of this bulwark arose in Hungary and Italy, and the disaster was attributed to the corruption and cowardice of Stephen Tomasevic. The Hungarian king Matthias Corvinus never forgave him; but the evidence seems to show that the surrender was the act of the inhabitants of the town, done in his despite.
Two years later King Stephen Thomas died, hampered in his struggle with the Turk by his feuds with his vassal and father-in-law, the ruler of Herzegovina, and with the Ban of Croatia, and above all by the estrangement in religion between himself and his folk. The storm broke upon his son Stephen, who, having apparently convinced Pope Pius II of his innocence in the loss of Semendra, was crowned by the Pope’s Legate, and reconciled with the Hungarian monarch. Meanwhile the anti-national policy of the kings was producing its effect. The oppressive measures adopted by them, at the instigation of the Pope and Hungary, towards the Patarenes, alienated many of that sect, who fled into Turkey or remaining in the country acted as spies for the Sultan, while some actually embraced Islam. Mohammad resolved to reduce Bosnia to complete subjection. When he sent an embassy to demand tribute, King Stephen, taking the envoy into a treasure-chamber, said, “Here is the tribute; but I have no mind to send it to the Sultan.” “It is a fine treasure to keep,” replied the envoy, “but I know not whether it will bring you luck; I fear, the reverse.” When however Stephen failed to gain any aid from Venice or from Ragusa (itself trembling at the danger of a Turkish attack), and heard of the equipment of a great Turkish army, he repented his boldness, and sent to Mohammad to offer the tribute and ask for a truce for fifteen years. His ambassadors found the Sultan at Hadrianople. The historian of the Bosnian war, Michael Konstantinovic, who was in the service of the Turks, was there at the time; and, hidden behind a chest, he overheard the conversation of two pashas who were in the confidence of Mohammad. They arranged that the demands of the Bosnian King should be granted, and the envoys dismissed on the Saturday; but on the following Wednesday the army was to start and overwhelm Bosnia, before any aid from Hungary or elsewhere could reach it. So it came to pass; and though Michael privately informed the Bosnian ambassadors of the perfidious intentions of the Sultan, they would not believe him. Having occupied the district of Podrinje, Mohammad attacked the royal residence, the mighty fortress of Bobovac; and here again the special condition of Bosnia affected the course of events. The defender, Prince Radak, was secretly a Patarine, though he had feigned to accept Catholicism; and he betrayed the town to the Turk. The Turk rewarded him by decapitation;—a strange policy on the part of a conqueror whose interest it was to encourage such treacheries. Jajce in the west of the land capitulated, and the King, who had fled to Kliuc, surrendered to Mahmud Pasha, receiving from him a written guarantee for his life and freedom. The lands directly under the Bosnian Crown were soon subdued, Stephen commanding the captains of his castles to yield; and Mohammad marched southward to subdue the Duchy and Ragusa. But in this difficult country he made little way; and, on failing to take the capital, Blagaj, he abandoned the enterprise. It was the Sultan’s policy to put to death all rulers whom he dethroned; and, in order to release him from the obligation of keeping a promise which he had not authorised, a learned Persian mufti with his own hand beheaded the Bosnian King. It is said that Mohammad carried off 30,000 boys to be made into Janissaries, besides 100,000 other captives. The Catholics who were left fled from the country; and to prevent its utter dispeoplement, Mohammad gave the Franciscans a safeguard, allowing the Christians free exercise of their religion. Henceforward the Franciscan influence was predominant.
King Matthias Corvinus made a vigorous attempt to rescue Bosnia; and in the year 1463 he drove many of the Ottoman garrisons out. But he had not made timely preparations for encountering the return of Mohammad, who in the next spring (1464) came to recover Jajce, the most important stronghold of all. The hard-pressed place was relieved by a Hungarian force; but at the end of the year Matthias, who was besieging another fort, was constrained by Mahmud Pasha to retreat. Nothing more was done for Bosnia. A strip in the north, with a few fortresses including Jajce, remained in the power of Hungary, and gave the title of “King of Bosnia” to the voivod of Transylvania; but the land as a whole had passed under Muslim rule. Herzegovina was made fully subject nearly twenty years later (1483). All the Slavonic powers of the Balkan peninsula were thus gathered into the Asiatic empire, except the tributary republic of Ragusa and a part of the principality of Montenegro, whose recesses afforded a refuge to many of those who saved themselves from the wreckage of the neighbouring countries. Stephen Crnoievic, the maker of Montenegro, had spent his life in defending his country against Mohammad’s father, Murad, and had fought hand in hand with Scanderbeg. He died in 1466. His son Ivan the Black continued the struggle with indomitable spirit, though the waves seemed to be closing over his head, when to south of him Albania was thrown open to the Turk by the death of Castriotes and Bosnia was conquered in the north. When the Venetians abandoned Scodra to Mohammad (1479), the very key of Montenegro seemed to have been surrendered; and so desperate appeared