Year 1420 was a leap year starting on Monday (link will display the full calendar) of the Julian calendar. Events of 1420 May 21 - Treaty of Troyes: With the Burgundian faction dominant in France, King Charles VI of France acknowledges Henry V of England as his heir and as virtual ruler of most of France. May 25 - Henry the Navigator is appointed governor of the Order of Christ. October 22 - Ghiyasu'd-Din Naqqah, an envoy of the embassy sent by the Timurid ruler of Persia, Mirza Shahrukh (… (More on 1420)