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."