Year 1403 (MCDIII) was a common year starting on Monday (link will display the full calendar) of the Julian calendar. Events January–December January / February – Treaty of Gallipoli: Süleyman Çelebi makes wide-ranging concessions to the Byzantine Empire and other Christian powers, in the southern Balkans. February 7 – King Henry IV of England marries as his second wife Joan of Navarre, the daughter of King Charles II of Navarre and widow of John IV, Duke of Brittany, at Winchester Cathedral. March 12 – As King Martin I of Aragon helps to end the siege by the French of the papal palace in Avignon, Antipope Benedict XIII flees to Aragon. March 23 – Stříbrná Skalice in Central Bohemia is razed by Sigismund of Luxembourg. April – Balša III succeeds his father Đurađ II as ruler of the Principality of Zeta (now the Republic of Montenegro). May 21 – Ruy Gonzalez de Clavijo, an ambassador from the king of Castile to Timur, leaves Cadiz; he arrives in Samarkand over a year later. Before July 21 – Henry 'Hotspur' Percy forms an alliance with Welsh rebel Owain Glyndŵr. July 21 – Battle of Shrewsbury: King Henry IV of England defeats a rebel army led by "Hotspur" Percy, who is killed in the battle. October 7 – Battle of Modon: The Genoese fleet under Jean Le Maingre (Marshal Boucicaut) is defeated by the Republic of Venice, at Modon in the Peloponnese. October – An English fleet organised by John Hawley of Dartmouth and Thomas Norton of Bristol seizes seven French merchant vessels in the English Channel. November – An English revenge raid on Brittany by Sir William Wilford captures 40 ships and causes considerable damage ashore. December – Local English forces defeat an attempted French raid on the Isle of Wight under Waleran III, Count of Ligny. Date unknown Jan Hus begins preaching Wycliffite ideas in Bohemia. In China, the Yongle Emperor of the Ming Dynasty moves the capital from Nanjing to Beijing. commissions the Yongle Encyclopedia, one of the world's earliest and largest known general encyclopedias. orders his coastal provinces to build a vast fleet of ships, with construction centered at Longjiang near Nanjing; the inland provinces are to provide wood and float it down the Yangtze River. The Temple of a City God is constructed in Shanghai. The Gur-e Amir Mausoleum is built in Samarkand by Timur, after the death of