The Battle of Agincourt on 25 October 1415 saw Henry V of England (r. 1413-1422) defeat an overwhelmingly larger French army during the Hundred Year's War (1337-1453). The English won thanks to the superior longbow, field position, and discipline. The French suffered from a reliance on heavy cavalry in poor terrain and the ill-discipline of their commanders.
This is a companion discussion topic for the original content at https://www.worldhistory.org/Battle_of_Agincourt/.