Pentecost, also known as Whitsunday, was formerly one of the greatest feast days of the medieval world, just after Easter and Christmas. It was the last day of Eastertide, commemorating the descent of the Holy Ghost on the Apostles ten days after the Ascension of the Lord. It was on Pentecost, so says Sir Thomas Malory, that the knights of the Round Table reconvened: "every year were they sworn at the high feast of Pentecost", renewing their vows of service and obedience to King Arthur. And, strengthened by the presence of the Holy Ghost, they were given a new quest and bidden on their way.
No medieval realm had a greater devotion to the Holy Ghost than France, where the culture of chivalry first took root. The most senior order of knighthood was the Order of the Holy Spirit, limited to one hundred knights (roughly analogous in prestige to Britain's Order of the Garter). Indeed, the entire kingdom seemed to rest on the Holy Ghost's authority: it was believed that, in the 5th century, when Saint Remigius was to baptize the warlord Clovis as the first Christian king of the Franks, he found that he had no oil to use for the anointing. The bishop placed the empty vial upon the altar of his church, where it was miraculously filled by the Holy Ghost. Others say that He descended in the form of a dove to place vial of holy oil in Remigius's hands. Either way, this same vial, according to legend, was used for the anointing at the coronation of every king of France until 1793, when it was destroyed by revolutionaries in yet another act of vandalism and cultural suicide.
The symbol of the holy vial, or ampulla, in French heraldry was the fleur-de-lis. Its three petals, recalling the Trinity, became the defining symbol of the monarchy's power. After Joan of Arc's execution at the hands of the English, King Charles of France rose her surviving family members to nobility, authorizing them to take on the surname du Lys. It was the least the king could do for the relatives of the peasant girl who led him to the coronation city of Reims in triumph.
And so, in remembrance of the Holy Ghost and the legend of the ampulla, I wore my fleur-de-lis necktie to Whitsunday Mass yesterday. I don't suppose anyone who saw it immediately got the reference.