Lupercalia was celebrated at the ides of February, or February 15. It was a fertility festival dedicated to Faunus, the Roman god of agriculture, as well as to the Roman founders Romulus and Remus.
Lupercalia survived the initial rise of Christianity but was outlawed at the end of the 5th century by Pope Gelasius, who declared February 14th as St. Valentine's Day due to its "un-Christian" nature. However, it was not until much later that the day became definitively associated with love.
WHO IS CUPID?
Cupid, often portrayed on Valentine's Day cards as a naked cherub launching arrows of love at unsuspecting lovers, has his roots in Greek mythology as the Greek god of love, Eros.
According to the Greek Archaic poets, Eros was a handsome immortal who toyed with the emotions of gods and men, using golden arrows to incite love and leaden ones to sow aversion. It wasn't until the Hellenistic period that he began to be portrayed as the mischievous, chubby child that we see depicted on Valentine's Day cards.