Would it surprise you to learn that those cards your child is folding into tiny envelopes for the class Valentine’s Day party probably have their origins in Third century Rome? Or that there were a number of “Saint Valentines” and no one really knows which one we honor on February 14? An estimated 1 billion valentines are mailed every year. Sure, they express love – but do you know why?

The most romantic theory about the origins of the holiday features the young priest Valentine, who continued to marry star-crossed lovers even after Roman Emperor Claudius II outlawed marriage for young men, believing single men made better soldiers. When his rebellion was discovered, Valentine was arrested and thrown into prison. Legend has it that he fell in love with a young woman--possibly his jailer’s daughter--who visited him, and sent her a love letter signed “from your Valentine.” He was condemned to death, but their love story lived on.

At the time, pagan Romans celebrated the official arrival of spring on February 15 with a fertility festival called Lupercalia. Young women wrote their names on slips of paper, dropped them in a large jar, and the city’s bachelors would withdraw the slips to find their romantic partners for the year. By the end of the Fifth century, the tradition had been outlawed as antithetical to Christian morality. In its place, Christians offered St. Valentine’s Day, a holiday that honored a Christian saint and preserved the spirit of Lupercalia.

By the Middle Ages, Valentine’s Day had become linked to love and romance. The British Library in London owns the oldest known Valentine, a letter written by Charles, the Duke of Orleans, to his wife while he was imprisoned in the Tower of London in 1415. Colonial Americans sent Valentines, and Esther Howland, “the Mother of the Valentine” began mass-producing Valentine’s Day cards in the United States in the 19th century.

Of course, exchanging cards isn’t the only way to celebrate the holiday. If you live in Korea or Japan, it’s only your lucky day if you’re male: February 14 is the day women present chocolates to their beloveds. (Men reciprocate on “White Day,” March 14.) In England, traditionalists eat buns baked with caraway seeds, plums and raisins. Hopeful young women can follow a custom dating back to Hamlet, where an early riser peering out the window on Valentine’s Day can hope to see the man she will marry. In Denmark, romantics send pressed white flowers called “snowdrops” and sign cards with dots, forcing recipients to guess the senders.

Or, there’s always flowers and chocolate….