When D’Artagnan slept with the pretty noblewoman Mylady, he sees her arm being burned with a fleur de lis: symbol of being a hardcore criminal. So far for the not too charming explanation of the 4th of the 3 musketeers 
The real Fleur de Lis history dates back to the first Merovingian king of the French or the Franks as they called themselves 1300 years ago. When this Frank/French king called Clovis became a Christian, it is said that an angel descended from heaven and offered him a golden lily as a symbol for purification.
This lily flower depicted with three petals will show up frequently to represent the French royalty as well as on English royalty when thy claimed to have conquered the French around the 12 century.
Of course Christianity merely put their interpretation on the fleur the lis which is really not a French invention. The flower was already depicted on pillars of temples many centuries earlier which makes the fleur de lis charm a timeless jewelry.
