Shortly after the fall of Constantinople the Ottoman Sultan Mehmet II
mobilized his army to march on Belgrade and from there possibly move
on to the European heartland.
In Hungary, the threat was considered especially grave news. It was clear that the sultan's next move would be against them. The Hungarians sent an army under the leadership of Janos Hunyadi to defend Belgrade.
In the summer of 1456 Turkish heavy artillery bombarded Belgrade and Mehmet ordered an all-out assault of the fortress city.
Hunyadi, however, directed the defense with great resourcefulness. He ordered the defenders to throw tarred wood, and other flammable material over the walls, and then set it afire. Soon a wall of flames separated the Turks fighting in the city from their comrades outside the walls.
Eventually the Ottomans were defeated and driven back. The sultan's defeat was hailed as a glorious victory for Christendom. The Turks would not attack Hungary for another 70 years, and Europe gained an important reprieve.