The French phrase fleur de lis means literally “flower of the lily”. The lily is associated with the Virgin Mary and her purity, and with the Archangel Gabriel, the angel of the Annunciation. A stylized image of a lily,* called the fleur-de-lis, has come to represent France and especially French monarchs.
The three petals can be seen as standing for the Holy Trinity. During the reign of King Louis IX they also came to represent faith, wisdom, and chivalry. This is not surprising since King Louis (1215-1270) was a monarch endowed with those virtues.
King Louis spent long hours in prayer, singing the Divine Office daily as if he were a monk. He fasted and fed beggars at his table. He did penance and cared for lepers. King Louis led Crusades from 1248-1249 and in 1270. He died near Tunis during the 1270 crusade.
At Tradition in Action, Prof. Plinio Correa de Oliveira discusses the attribute of wisdom found in St. Louis IX:
“Our Lady was the Seat of Wisdom and was always seeking to increase her knowledge, love and service of God.In 1297, less than thirty years after King Louis’ death, Pope Boniface VIII raised him to the altar as a Catholic saint, and we celebrate his feast day today, August 25.
“This virtue is demanded of kings, governors, and anyone who exercises some form of power. A king without wisdom loses his people. When he has wisdom, he saves his people, and is the glory of his people. For a man without wisdom, power becomes an instrument of his perdition.
“Hence, we can understand the magnificent eulogy Scriptures made of the wise king. He leads peoples and things to their last end, which is God. This is the ultimate meaning of his kingship.
“What we admire in St. Louis, King of France, is the model of a wise man placed on the throne to govern his kingdom.”
Toison D’or le Roi de France [Golden Fleece King of France] from Wikimedia Commons. In the public domain.
*There is some controversy over whether the fleur-de-lis represents a lily or a yellow flag iris. Given the importance of the lily in religious iconography, however, the better view is that it represents the lily.