1404

January–December

• June 14 - Rebel leader Owain Glyndŵr, having declared himself Prince of Wales, allies with the French against the English. He later begins holding parliamentary assemblies.
• October 17 - Pope Innocent VII succeeds Pope Boniface IX, as the 204th pope.
• November 19 - St. Elizabeth's flood: A flood of the North Sea devastates parts of Flanders, Zeeland and Holland.

  Date unknown

• Jean de Béthencourt becomes the first ruler of the Kingdom of the Canary Islands.
• Stephan Tvrtko II succeeds Stefan Ostoja as King of Bosnia.
• Peace is declared between Lithuania and the Teutonic Knights, after they agree to exchange land and form an alliance against Muscovy.
• Wallachia reaches its maximum extent under Mircea cel Bătrân.
• The University of Turin is founded.
• Timur is hit by a fever, while preparing to invade China.
• Centurione II Zaccaria succeeds Maria II Zaccaria, as ruler of the Principality of Achaea.
• Virupaksha Raya succeeds Harihara Raya II, as ruler of the Vijayanagara Empire in present-day southern India.
• Narayana Ramadhipati succeeds Ponthea Yat, as King of Cambodia.
• Ruaidri Caech MacDermot succeeds Conchobair Óg MacDermot, as King of Magh Luirg, in present-day north-east Connacht, Ireland.
• The city of Vicenza comes under the rule of the Venetians.