|The original Valentine's day in the Ides of
February was Rome's Lupercalia, a festival of sexual celebration. Young
virile men chose partners for erotic games by drawing "billets" - small
pieces of paper with women's names on them.
christians denounced this Heathen custom as lewd. churchmen tried to substitute saints names and short sermons on the billets, however they failed to convince the people that this had anything to do with the season of rebirth.
February is sacred to Juno Februata, Goddess of love and fertility. Not being able to convert the people at his time, the church instead replaced her with a mythical martyr, St. Valentine. So St. Valentine became the christian patron of lovers perforce, and the festival remained dedicated to lovers. It is interesting to note, that even in its christianised form, the Valentinian celebration involved secret sex worship, called "a rite of spiritual marriage with angels in a nuptial chamber."