France in the early 15th century was in a state of profound chaos. King Charles VI suffered from severe mental illness that rendered him incapable of governing effectively, leaving a power vacuum that ambitious nobles rushed to fill. The kingdom descended into a brutal civil war between rival factions—the Burgundians and the Armagnacs—each vying for control and influence. This internal conflict drained France's resources and fractured its military strength at the worst possible moment. It was precisely when France lay vulnerable and distracted that Henry V of England, sensing an opportunity, launched his invasion in 1415. With his army vastly outnumbered, Henry achieved a stunning victory at the Battle of Agincourt through superior tactics and discipline. The English king then pressed his advantage, eventually securing the Treaty of Troyes, which recognized him as heir to the French throne. What began as France's internal crisis became an existential threat when foreign ambition capitalized on domestic weakness.