Valentine's Day, observed on February 14th, has roots that predate Christianity by many centuries, originating as a Roman fertility and purification feast dedicated to the god Lupercus. Lupercus, associated with wolves through the Latin root "lupus," was revered as a god of the hunt and fertility. The festival around this date included peculiar rituals, such as young men or priests whipping women with goat thongs, believed to promote fertility or ensure a safe birth. This practice may also connect to the Roman god Faunus, sometimes conflated with Lupercus, who was depicted as a goat-like figure with horns. Over time, these pagan customs of Lupercalia melded with later traditions, influencing the modern celebration of Valentine's Day.

As far back as documented history goes, the celebration of February 14 can be traced to ancient Roman fertility festivals, including the Lupercalia on February 15, honoring the god Lupercus. The Romans considered Lupercus closely related to Faunus, with some historians suggesting they might be the same god under different regional names. The main center of the Lupercalia celebrations was the cave of the Lupercal on Rome's Palatine Hill, linked to the legendary founders of Rome, Romulus and Remus, who were supposedly nursed by a she-wolf, a connection reflected in the terms Lupercal, Lupercus, and Lupercalia derived from the Latin and Greek words for wolf. Some traditions even claim Romulus and Remus instituted the Lupercalia feast. Rituals during the Lupercalia included two young priests running nearly naked around the old city walls in mid-February, striking bystanders with thongs from sacrificed animals, believed to cure sterility. Another rite involved a purification ceremony for Roman women by the priests of Pan Lyceus. The feast of Lupercalia was deeply significant to the Romans, regarded as one of the oldest and most important festivals, with prominent noble families like the Fabius and Quinctilius tasked with its annual organization. Despite the arrival of Christianity in Rome, the Lupercalia persisted until AD 494, when Pope Gelasius I transformed it into the feast of the Purification, substituting a pagan purification ritual with a different observance.

The Roman god Lupercus, akin to the Greek god Pan and known as Bal or Baal among the Phoenicians and Semites, is central to the origins of Valentine's Day. Historically tied to Nimrod, a mighty hunter in defiance of the LORD, Lupercus is honored in the pagan festival of Lupercalia, celebrated in ancient Rome on February 14 and 15. This sensuous festival encouraged licentious acts of sexual immorality among young people, starkly opposing God's way of love. During Lupercalia, priests called Luperci, dressed only in goatskin girdles, sacrificed goats and a dog, then ran through the city striking women with goatskin strips named februa, believed to purify and remove infertility. The festival also connected to the legendary she-wolf who suckled Remus and Romulus, founders of Rome, with "wolf" as slang for a sexually available woman, linking the day to Venus, goddess of sexual love, and her son Cupid. This lewd celebration of lust was immensely popular among Romans, a popularity that persisted as the festival was later Christianized in AD 496 by Pope Gelasius, who renamed it Saint Valentine's Day and shifted its observance to February 14. Despite this renaming, the core pagan elements and sensual nature of the original Lupercalia remained influential in the modern celebration of Valentine's Day.

Valentine's Day is a continuation of the ancient Roman rite of Lupercalia, observed on February 15 to honor the fertility god Lupercus. This festival involved the sacrifice of goats and a dog, with goats' blood smeared on the foreheads of two young men and then wiped off with wool dipped in milk. Young men, clad only in goatskin, ran around the Palatine hill, striking women with goatskin strips to ease labor for the pregnant and to promote fertility in others. Lupercus, known as a hunter of wolves, was linked to the Roman god Faunus, associated with agriculture and fertility, and traced to the Greek god Pan, a deity of woods, fields, and flocks, depicted with a human torso but the legs, horns, and ears of goats. This imagery aligns with the use of goats in the rituals of Lupercalia. The celebration, often seen as an excuse to lower morals under the guise of religion, was tied to fertility and sensuality. The date of the observance shifted from February 15 to the evening of February 14 in ancient times, as days were counted from sunset, and later adjusted by Roman calendar changes and papal decree in AD 496. Additionally, during Lupercalia, the tradition of drawing names of young women from a box by men as chance directed gave rise to the custom of exchanging Valentines.