Crusade of Varna The Crusade of Varna was a string of events in 1443 – 44 between the Kingdom of Hungary , the Serbian Despotate , the Principality of Wallachia and the Ottoman Empire . It culminated in a devastating Christian loss at the Battle of Varna on November 10 , 1444 . Background . In 1428 , while the Ottoman Empire was fighting a war with the Republic of Venice , the Ottomans and the Kingdom of Hungary achieved a temporary peace by establishing the Serbian Despotate as a buffer state . After the war ended in 1430 , the Ottomans returned to their earlier policy of controlling all lands south of the Danube . In 1432 , Sultan Murad II began raiding into Transylvania . After King Sigismund died in 1437 , the attacks intensified , with the Ottomans occupying Borač in 1438 and Zvornik and Srebrenica in 1439 . At the end of 1439 , Smederevo capitulated and Murad succeeded in making Serbia an Ottoman province . Đurađ Branković , Despot of Serbia , fled to his estates in Hungary . In 1440 , Murad besieged Hungary ' s main border fortress , Belgrade . After failing to take the fortress , he was forced to return to Anatolia to stop attacks by the Karamanids . Meanwhile , Sigismund ' s successor Albert had died in October 1439 , shortly after signing a law to " restore the ancient laws and customs of the realm " . The law restricted the royal authority by requiring the participation of landed nobility in political decisions . Four months after Albert ' s death , his only son , Ladislaus , was born while Hungary was in the midst of a civil war over the next monarch . On July 17 , 1440 , Vladislaus , king of Poland , was crowned despite continuing disputes . John Hunyadi aided Vladislaus ' s cause by pacifying the eastern counties , gaining him the position of Voivode of Transylvania and the corresponding responsibility of protecting Hungary ' s southern border . By the end of 1442 , Vladislaus had secured his status in Hungary , and denied an Ottoman proposal of peace in exchange for Belgrade . The Roman Catholic Church , meanwhile , had long been advocating for a crusade against the Ottomans , and with the end of both the Hungarian civil war and a nearly simultaneous one in Byzantium , they were able to realistically begin negotiations and planning . The impetus required to turn the plans into action was provided by Hunyadi between 1441 – 42 . In 1441 , he defeated a raid led by Ishak Pasha of Smederevo . He nearly annihilated Mezid Bey ' s army in Transylvania on March 22 , 1442 , and in September he defeated the revenge attack of Şihabeddin Pasha , governor - general of Rumelia . Branković , hoping to liberate Serbia , also lent his support after Novo Brdo , the last major Serbian city , fell to the Ottomans in 1441 . The Crusade . Early fighting . On January 1 , 1443 , Pope Eugene IV published a crusading bull . In early May , it was reported " that the Turks were in a bad state and that it would be easy to expel them from Europe " , though the success of the crusade still required the simultaneous attacks of both the Hungarian and Karamanid armies . However , in the spring of 1443 , before the Hungarians were ready , the Karamanids attacked the Ottoman Empire and were devastated by Murad ' s full army . The Hungarian army , led by Vladislaus , Hunyadi , and Branković , attacked in mid - October . They correctly expected that Murad would not be able to quickly mobilize his army , which consisted mainly of fief - holding cavalrymen who needed to collect the harvest to pay taxes . Hunyadi ' s experience of winter campaigns from 1441 – 42 added to the Hungarian ' s advantage . They also had better armor , often rendering the Ottoman weapons useless . Murad could not rely on the loyalty of his troops from Rumelia , and had difficulties countering Hungarian tactics . As the Hungarians advanced , they forced Kasim Pasha of Rumelia and his co - commander Turahan Bey to abandon camp and flee to Sofia , Bulgaria to warn Murad of the invasion . However , the two burned all the villages in their path in an attempt to wear down the Hungarians with a scorched earth tactic . When they arrived in Sofia , they advised the Sultan to burn the city and retreat to the mountain passes beyond , where the Ottoman ' s smaller army would not be such a disadvantage . Shortly after , bitter cold set in , and the next encounter , fought at Zlatitsa Pass just before Christmas 1443 , was fought in the snow . The Hungarians were defeated . As they marched home , however , they ambushed and defeated a pursuing force in Dragoman Pass , where Mahmud Bey , son - in - law of the Sultan and brother of the Grand Vizier Çandarlı Halil Pasha , was taken prisoner . While the battle at Zlatitsa Pass had been a disaster , the ambush returned to the Hungarians the illusion of an overall Christian victory , and they returned triumphant . The King and Church were both anxious to maintain the illusion and gave instructions to spread word of the victories , but contradict anyone who mentioned the loss . Murad , meanwhile , returned angry and dejected by the unreliability of his forces , and imprisoned Turahan after blaming him for the army ' s setbacks and Mahmud Bey ' s capture . Peace proposals . Murad is believed to have had the greatest wish for peace . Among other things , his sister begged him to obtain her husband Mahmud ' s release , and his wife Mara , daughter of Đurađ Branković , added additional pressure . On March 6 , 1444 , Mara sent an envoy to Branković ; their discussion started the peace negotiations with the Ottoman Empire . On April 24 , 1444 , Vladislaus sent a letter to Murad , stating that his ambassador , Stojka Gisdanić , was travelling to Edirne with full powers to negotiate on his behalf . He asked that , once an agreement was reached , Murad send his own ambassadors with the treaty and his sworn oath to Hungary , at which point Vladislaus could also swear . That same day , Vladislaus held a Diet at Buda , where he swore before Cardinal Julian Cesarini to lead a new expedition against the Ottomans in the summer . The strongest remaining supporter of Ladislaus ' claim for the throne also agreed to a truce , thus removing the danger of another civil war . Between June and August , 1444 , negotiations for a treaty were carried out , first in Edirne , and then in Szeged . The Hungarians were not entirely interested in peace , however , especially with Cesarini pushing for the crusade ' s continuation . The Cardinal eventually found a solution that would allow for both the continuation of fighting , and the ratification of the treaty , and on August 15 , 1444 , the Peace of Szeged was sworn into effect . Final stage . Shortly after all the short - term requirements of the treaty were fulfilled , the Hungarians and their allies resumed the crusade . Murad , who had retired shortly after the treaty was completed , was called back to lead the Ottoman army . On November 10 , 1444 , the two armies clashed at the Battle of Varna ( near the Black Sea fortress of Varna , Bulgaria ) . The Ottomans won a decisive victory despite heavy losses , while the Hungarians lost their King and over 10 , 000 men . Aftermath . Many were crippled by frostbite , many more died in smaller follow - up battles , and most European prisoners were killed or sold into slavery . Hungary fell back into civil war until Hunyadi was elected Regent for the infant Ladislaus in June 1446 . Branković retained control over Serbia . The Ottoman Empire was free , for several decades , from any further serious attempts to push it out of Europe .