Battle of Varna
The reign of the young Władysław III (1434–44), who succeeded his father Władysław II Jagiełło and ruled as king of Poland and Hungary, was cut short by his death at the Battle of Varna against the forces of the Ottoman Empire. This disaster led to an interregnum of three years that ended with the accession of Władysław's brother Casimir IV Jagiellon in 1447.