The Hundred Years’ War was fought over 126 years (1337-1453).
The British won most of the battles, but the French won the war.
The main reason for the war from day one was for control over the French throne.
The two primary Houses involved in the conflict were the House of Valois and the House of Plantagenet, also known as the House of Anjou.
Although the conflict lasted 116 years, it was punctuated by several periods of peace. 100 years of non-stop fighting would be insane, even for humans.