May 9Treaty of Windsor between Portugal and England is ratified at Windsor cementing and strengthening ties between the two kingdoms. The treaty guarantees the mutual security of both nations and strengthens commercial ties. It is the oldest diplomatic alliance still in force. [1]
Jul 9 Battle at Sempach: Swiss beat Duke Leopold III of Austria
Jun 24 Saint John of Capistrano, Franciscan friar and Catholic priest from the Italian town of Capestrano, Abruzzo, born in Capestrano, Abruzzi, Kingdom of Naples (d. 1456)
Sep 16 Ambrose Traversari, Italian theologian and monk, born in Portico di Romagna, Forlì, Papal States (d. 1439)