Answer:
The war saw the introduction of new military technologies and tactics, such as the longbow and gunpowder artillery, which made knights less effective on the battlefield.
As the war progressed, the cost of equipping and maintaining a knight became increasingly expensive, while their effectiveness in battle diminished. The traditional image of a knight charging into battle on horseback with a lance became less viable as infantry armed with longbows could outshoot them, and gunpowder artillery could easily penetrate their armor. Furthermore, the use of mercenaries and foot soldiers became more common in armies, as they were less expensive to equip and maintain than knights.
The cost of maintaining large numbers of knights became a burden on both sides of the conflict, and the expense of outfitting and supporting large numbers of heavily armored knights led to a shift towards more cost-effective infantry-based armies. This shift away from the use of knights as the primary military force marked a decline in their value and status on the battlefield. Thus, the Hundred Years' War played a significant role in decreasing the value of armed knights and contributed to the end of the age of chivalry.