The Battle of Kosovo took place on June 15, 1389
Why didn't the Hungarians help the battle of Kosovo?
- Hungary was a powerful country but had its own troubles to deal with prior to dealing with the Ottomans.
- The Serbians were Eastern Orthodox Christians, Hungarians were Catholic. Thus they were not traditional allies.
- Hungary didn't really perceive the Ottomans as a serious threat until Serbia's acceptance of their rule in 1390 which effectively brought the Ottoman Empire to Hungary's frontier.
The Kingdom of Hungary reached the peak of its power under Louis the Great (1342–1382) who was a superior military leader. When Louis died in 1382, his daughter Mary, Queen of Hungary was crowned. However, most of Hungary's noblemen objected being ruled by a woman. A rival for Mary's crown, Charles III, arrived from Naples in 1385 and claimed Mary's throne. Although Mary was forced to abdicate, and Charles was elected King by the Hungarian Diet, Mary's supporters murdered Charles in Feb 1386. A Catholic Bishop got involved and tried to nominate Charles's infant son to the crown in the same year Charles was murdered. They succeeded in capturing Queen Mary. Eventually Queen Mary's husband (Sigismund of Luxembourg) emerged as the compromise candidate for the throne of Hungary in July 1386. Sigismund was consolidating his power and defending his crown from Queen Mary's sister (Queen Jadwiga of Poland), who invaded and was defeated in 1395.
It wasn't until Serbia accepted the Ottoman Sultan's suzerainty (1390), and brought the Ottoman empire to the boarders of southern Hungary that Sigismund perceived them as a threat. He didn't have the opportunity to attack them until 1396 at the Battle of Nicopolis.
Sigismund was defeated at Nicopolis, but eventually became King of Germany, King of Bohemia, and in 1433, Holy Roman Emperor.