May 9– The English Parliament closes its session for the year, and royal assent is given by King Henry IV to various acts, including the Sealing of Cloths Act 1409 and the Unlawful Games Act.
May 17– At Pisa, Cardinal Baldasare Cossa is elected by members of the Council of Pisa as the successor to the "antipope" Alexander V, who had died on May 4. On May 25, Cossa takes the name "John XXIII", a name that will be used more than 500 years later in 1958 when Angelo Giuseppe Roncalli is crowned as Pope John XXIII.
May 19– During his campaign against the Eastern Mongols, China's Emperor Cheng Zu stops with his troops at Minluanshu and orders the carving of an inscription on rocks at the north bank of the Kerulen river, declaring "In the eighth year of the Yongle geng yin, fourth month ding you, sixteenth day ren zi, the Emperor of the Great Ming passed here with six armies during the punitive expedition against the barbarian robbers."
May 31–King Martin I of Aragon (who is also King Martin II of Sicily) dies at the age of 53, leaving a question of who his successor will be, and five contenders for the thrones of both nations argue until the crown is awarded to Martin's nephew, Ferdinand, in 1412.
At the Onon River, the Chinese Army, under the command of the Emperor Cheng Zu, annihilates the Mongol forces of the KhaganÖljei Temür Khan, also known as Bunyashiri. The Khagan escapes and the Chinese troops pursue Arughtai, chingsang of another branch of the Northern Yuan.
September 19– After nearly two months of no progress against the defending Teutonic Knights, and the dissatisfaction of the Lithuanians and Poles in continuing a long-term conflict, the siege of Marienburg is lifted.
December 10– The Teutonic Council, led by the Grand Master Heinrich von Plauen, and King Jogalia of Poland and Duke of Lithuania enter into a 32-day truce.
↑Neillands, Robin (2001). The Hundred Years War. London: Routledge. p.196. ISBN0-415-26131-7.
↑"John XXIII", by J. P. Kirsch, in The Catholic Encyclopedia (New York: Robert Appleton Company, 1910)
↑Hlavacek, Ivan (2000). "The Empire:The Luxembourgs and Rupert of the Palatinate, 1347-1410". The New Cambridge Medieval History. Vol.6:c.1300-1415. Cambridge University Press.
12Rossabi, Morris (1998). "The Ming and Inner Asia". The Cambridge History of China, Volume 8: The Ming Dynasty, 1398–1644, Part 2. Cambridge University Press. p.229. ISBN9780521243339.
↑Chan, Hok-lam (1998). "The Chien-wen, Yung-lo, Hung-hsi, and Hsüan-te reigns, 1399–1435". The Cambridge History of China, Volume 7: The Ming Dynasty, 1368–1644, Part 1. Cambridge University Press. p.226. ISBN9780521243322.
↑Knoll, Paul W. (1983). "In Search of the Battle of Grunwald. Review of Die Schlacht bei Tannenberg 1410, Quellenkritische Untersuchungen, vol. I: Einführung und Quellenlage by S. Ekdahl". The Polish Review. 28 (3): 67–76. JSTOR25777993.
↑Jan Dlugosz, and Maurice Michael, translator, The Annals of Jan Długosz: A History of Eastern Europe from A. D. 965 to A. D. 1480 (IM Publications, 1997), pp. 399-401