Valentine's Day. Who invented it? Well, supposedly it is based in the Roman Lupercalia, a huge festival with sacrificed goats and pairing of bachelors and bachelorettes. Crops and women were slapped with bloody goat skins to make them both fertile for the coming year. Cool, huh?
Old Pope Gelasius deemed the event "unChristian" and changed the day to St. Valentine's day (although no one quite know which Valentine it was named for). But how it became known at the day of love remains a mystery. There were some places in old Europe that believed it was the day that started the birds mating season. I had no idea birds used a calendar!