May 30 is the memorial of Joan of Arc's death.
Those who don't know the story - a young girl heard a message from God, she went before the uncrowned king of her country to deliver that message, he sent he with an army to raise a siege in Orleans, the king was legitimately crowned, more military operations, she is captured and ransomed by the enemy, the put her on trial for heresy and witchcraft, May 30 1431 she is burnt at the stake, 50 years later the trial is declared to wrong and she is vindicated (a bit late).
Joan is considered Patron of; France, Soldiers, Prisoners, Young women, Rape Victims and several other things by the Catholic church.
If you want more info you should be able to find through a google search or your local library.