Twenty-four years after the death of Emperor Anthemius, a "Christianized" form of the festival of Lupercalia was officially adopted by the church as a time to honor Saint Valentine.
"Early Christians were happier with the idea of a holiday (Valentine's) honoring the saint of romantic causes than with one recognizing a pagan festival. In 496 A.D., Pope Gelasius named February 14 in honor of St. Valentine as the patron saint of lovers. " (How Valentine's Day Works, Apr. 1, 2000, retrieved Jan. 11, 2011)
February 14th as the day to honor this "saint" (the Catholic Church currently recognizes at least three different martyred saints named Valentine or Valentinus) stayed on the church's Calendar of Saints until 1969 A.D. Pope Paul VI removed it from the calendar.
What was the festival of the Lupercalia?
The Lupercalia festival was partly in honor of Lupa, the she-wolf who (according to legend) nursed the infant orphans Romulus and Remus. Roman legend states that Romulus and Remus founded the city of Rome in 753 B.C. The pagan festival was also in honor of the Roman god Lupercus who was the god of shepherds. Lupercus was Rome's equivalent to the Greek god Pan.
The link between the Lupercalia, fertility, and romance in general is evident in the festivities that occurred during the celebrations (Valentine's Day, History Channel web site, retrieved Jan. 10, 2011).
The Greek historian Plutarch (c. 46 to 120 A.D.) also describes the Lupercalia and its relationship to fertility. The second-century Christian apologist Justin Martyr further links the worship of pagan gods to the Lupercalia when he writes of an image of "the Lycaean god, whom the Greeks call Pan and the Romans Lupercus," who is nude save for a girdle of goatskin, which stood in the Lupercal, the cave where Romulus and Remus were suckled by a she-wolf.
Red roses were the favorite flower of Venus, the Roman goddess of love. Red is also a color that signifies strong feelings.
In Roman mythology, Cupid is the god of desire, affection, and erotic love. Cupid today appears shooting his bow to inspire romantic love.
It is unclear the origin of the familiar heart shape used for Valentine's celebration. One possibility involves the now-extinct North African plant silphium. The city-state of Cyrene had a lucrative trade in the plant, which looks just like the heart shape used in modern times.
Sources: Where did the ubiquitous Valentine's symbol come from? from Slate.com
Does it MATTER?
Does it matter that the church adopted an ancient festival used to worship pagan gods and promote fertility to worship the God of the Bible? Does God really CARE what customs are used to worship and honor Him or whether or not we celebrate the Valentine's holiday? Notice the following warning God gave to ancient Israel.
"When the Lord your God cuts off from before you the nations which you go to dispossess, and you displace them and dwell in their land, take heed to yourself that you are not ensnared to follow them, after they are destroyed from before you, and that you do not inquire after their gods, saying, 'HOW DID THESE NATIONS SERVE THEIR GODS? I ALSO WILL DO LIKEWISE.' "
"You shall NOT worship the Lord your God in that way; for every abomination to the Lord which He hates they have done to their gods . . . " (Deuteronomy 12:29-31, NKJV)
Note that the issue in this passage is NOT the worship of other gods. The warning is to not adopt CUSTOMS used to worship or honor other gods in order to serve and worship the true God.
The true origin of Valentine's Day and its symbols are rooted in the worship of false gods. It has no Biblical basis. Those who celebrate the holiday and consider themselves believers in the God of the Bible need to take a prayerful look at what they are doing.