Question: Battle of Kosovo was the culmination of a Hungarian offensive to avenge the defeat in a battle that took place on which day ?
Sentence (from "Battle of Varna"): The Ottoman Army under Sultan Murad II defeated the Hungarian–Polish and Wallachian armies commanded by Władysław III of Poland (also King of Hungary), John Hunyadi (acting as commander of the combined Christian forces) and Mircea II of Wallachia.
Relevant evidence: No