Major Events
- Mar 1 Pope Martinus I calls for crusade against the Hussite protestants
- Apr 21 Treaty of Saint Maartens Dike
- May 21 Treaty of Troyes: Henry V of England and his heirs will inherit the throne of France upon the death of King Charles VI of France (later rendered moot by the military victory of Charles VII)
- May 23 Jews of Syria and Austria expelled
- May 25 Henry the Navigator is appointed governor of the Order of Christ
- Jun 7 Troops of the Republic of Venice capture Udine, ending the independence of the Patriarchate of Aquileia
- Jul 14 Battle at Vitkov Zizka's hill (Prague): Taboriets beat Bohemia
- Aug 5 Duke John VI of Bavaria visits Dutch mystic Lidwina (Christ's bride)
- Aug 7 Construction begins on the dome of Florence Cathedral, designed by Renaissance architect Filippo Brunelleschi
- Oct 28 Beijing is declared the capital of the Ming dynasty under the Yongle Emperor
- More 1420 Events
Born in 1420
- Aug 24 Albrecht van Eyb, German humanist (Bamberg & Eichstattt), born in Ansbach, Germany (d. 1475)
- Oct 14 Tomas de Torquemada, Castilian Grand Inquisitor during Spanish Inquisition, born in Torquemada (or Valladolid), Kingdom of Castile (d. 1498)
- Nov 24 John Stafford, 1st Earl of Wiltshire, English politician (d. 1473)
Who Died in 1420
- Aug 9 Pierre d'ailly [Peter de Alliaco], French theologist and cardinal, dies
- Sep 3 Robert Stewart, 1st Duke of Albany, regent of Scotland
Famous Weddings in 1420
- Jun 2 Henry V of England (33) marries Catherine of Valois (18), youngest daughter of King Charles VI of France at Troyes Cathedral