1404

Year 1404 (MCDIV) was a leap year starting on Tuesday (link will display the full calendar) of the Julian calendar.

January–December

 * April or May – Battle of Blackpool Sands: Local English forces defeat an attempted raid from Saint-Malo on the port of Dartmouth, Devon; the French commander, William du Chastel, is killed.
 * 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 northeast Connacht, Ireland.
 * The city of Vicenza comes under the rule of the Venetians.

Births

 * January 18 – Sir Philip Courtenay, British noble (d. 1463)
 * February 14 – Leon Battista Alberti, Italian painter, poet, and philosopher (d. 1472)
 * March 25 (bapt.) – John Beaufort, 1st Duke of Somerset, English military leader (d. 1444)
 * June – Murad II, Ottoman Sultan (d. 1451)
 * July 6 – Yamana Sōzen, Japanese warlord and monk (d. 1473)
 * July 25 – Philip I, Duke of Brabant (d. 1430)
 * September 30 – Anne of Burgundy (d. 1432)
 * September – Gilles de Rais, French aristocrat (d. 1440)
 * October 14 – Marie of Anjou, queen of Charles VII of France (d. 1463)

Deaths

 * April 27 – Philip II, Duke of Burgundy (b. 1342)
 * September 14 – Albert IV, Duke of Austria (b. 1377)
 * September 27 – William of Wykeham, English bishop and statesman (b. 1320)
 * October 1 – Pope Boniface IX (b. 1356)
 * October 15 – Marie Valois, French princess (b. 1344)
 * December 13 – Albert I, Duke of Bavaria (b. 1336)
 * date unknown – Eleanor of Arborea, ruler of Sardinia (b. 1350)