The central issue of the Hundred Years' War was the rightful claim to the French throne. The conflict began in 1337 between the Kingdom of England and the Kingdom of France, largely due to territorial disputes and dynastic succession. The English king, Edward III, claimed the French crown through his mother, a French princess, challenging the legitimacy of the Valois dynasty. Additionally, control over valuable territories like Aquitaine and Flanders fueled tensions. The war spanned over a century, witnessing significant battles, such as Crécy and Agincourt, and ultimately led to profound changes in both kingdoms and the rise of national identities.