The significance of the Hundred Years' War, which lasted from 1337 to 1453, lies in its profound effects on both France and England. This extended conflict reshaped national identity, as both countries developed a sense of national consciousness tied to their respective monarchies and conflicts. Additionally, the war saw the rise of new military tactics and the decline of feudalism, paving the way for centralized monarchies. It also contributed to significant social changes, including shifts in the balance of power between the nobility and the monarchy. Ultimately, it set the stage for the Renaissance and later European power dynamics.