The hunded years war was fought between France and Britain over control of France. The war lasted over a hundred years hence its name. The fighting started in 1337 when King Philip VI of France decided to capture a portion of southwest France that was controlled by the English.
Joan of arc was a child who was chosen by God to lead the French to victory. She had dreams that Saints were speaking to her and instructing her to lead the French army.
Eventually Joan took her story to the king and since he too was a very faithful person her believed her and let her help lead his troops.
Joan slowly convinced the army that she was worthy of leading them in battle by showing that every decision she made had a positive outcome for them.
Many years later, Joan was captured by the Burgundians, who sold her to the English.