May 15, 1440
Coronation of Władysław III as King of Hungary
On May 15, 1440, in Székesfehérvár, Władysław III of Varna was crowned King of Hungary. This event initiated a personal union between Poland and Hungary, creating a powerful alliance against the Ottoman Empire. On the same day, the controversial coronation of the three-month-old Ladislaus the Posthumous also took place.
