Key moments defining Joan of Arc's life include her visions, which she claimed were messages from divine sources, guiding her to support Charles VII during the Hundred Years' War. At a young age, she gained military leadership and played a significant role in lifting the siege of Orléans. Her capture and subsequent trial for heresy showcased the tension between faith and politics. Joan's martyrdom at the stake solidified her legacy as a symbol of patriotism and divine mission, leading to her canonization as a saint and a national hero in France.