Historical events that had taken place in the late 14th and early 15th century greatly altered the political circumstances in the Balkans, especially following the defeat of the Ottoman army at the battle of Angora in 1402. The defeat and captivity of Sultan Bayezid I caused a political crisis in the Ottoman Empire. Those historical circumstances went in favor of Knez Stefan Lazarević, the ruler of Moravian Serbia, who was honored with the title of Despot by the Byzantine emperor. Despot was the highest rank one could be awarded other than emperor, so the act of awarding such a high honor was of great political significance. This persuaded Hungarian King Sigismund to make a deal with the Serbian monarch with the goal of shielding Hungarian borders from Ottoman invasions. With that deal, the Despot gained control of Belgrade in exchange for vassal obligations towards the Hungarian Kingdom. Based on indirect historical sources it is believed that the deal was made around 1403/1404.
