The custom of sending valentine cards actually became popular in the 1700s, with commercial valentines appearing in the early 1800s as entrepreneurs began to profit from the holiday. Valentine's Day eventually became so popular in the United States that a 1863 periodical claimed it was second in popularity only to Christmas.

Valentine's Day supposedly acquired its name from a Catholic saint, although exactly who he was is a matter of debate. The two most famous candidates were a priest in Rome and a bishop in central Italy, both of whom suffered martyrdom in the last half of the third century. Some have claimed this priest is associated with romance and love because he secretly performed Christian weddings during the Roman persecution.

Throughout the Middle Ages, Valentine's Day became increasingly popular in Europe. "English literature, following Chaucer, contains frequent references to February 14 as sacred to lovers (and) Shakespeare… and the diarist Samuel Pepys several times discuss(ed) the day and its related customs.” (Jane Hatch, The American Book of Days, 1978, p. 178).

What was specific to Feb.13 through 15 in the Roman calendar was the pagan festival of Lupercalia. Robert Myers, in Celebrations: The Complete Book of American Holidays writes: "The most plausible theory for St. Valentine's Day traces its customs back to the Roman Lupercalia, a feast celebrated in February in honor of the pastoral god Lupercus, a Roman version of the Greek god Pan. The festival was an important one for the Romans and, occurring when it did, naturally had some aspects of a rebirth rite to it" (pp. 50-51).

The Lupercalia festival was celebrated in honor of a number of pastoral deities. It combined the idea of cleansing before spring renewal with the promotion of sexual fertility and reproduction, a prevalent theme throughout pagan religion. Young men dressed in the skins of sacrificed goats would run from the Lupercal cave brandishing strips of goat skin as whips. Any women slapped by these were assured fertility and ease in childbirth. (The Encyclopaedia Britannica, Vol. 15, 9th edition, "Lupercalia").

As Christianity spread throughout the Roman Empire, it was common for pagan converts to retain their earlier religious customs and practices. Edward Gibbon, in his classic work The History of the Decline and Fall of the Roman Empire, states: "After the conversion of the Imperial city, the Christians still continued, in the month of February, the annual celebration of the Lupercalia; to which they ascribed a secret and mysterious influence on the genial [generative or reproductive] powers of the animal and vegetable world" (chap. 36).

Pope Gelasius is said to have eradicated Lupercalia from Christian observance in the last decade of the fifth century, but the intermingling of paganism and Christianity had become inseparable in much of the Western world. Saturnalia and Mithraism were incorporated into the church through claiming a December birth date for Jesus Christ. Various spring fertility rites merged to form the basis of Easter celebrations, and Lupercalia evolved into the observance of St. Valentine's Day.

In a similar fashion the Catholic church canonized saints who were celebrated with his or her own feast day and attributed with spheres of responsibility previously attributed to the various pagan gods. St. Stephen is the patron saint of stonemasons; doctors are to pray to St. Luke, fishermen to St. Andrew and carpenters to St. Joseph. There are patron saints for farmers, hunters, shoemakers and even comedians. And then there is the patron saint of love and romance, St. Valentine.

God warned ancient Israel not to mix pagan customs with worshipping Him as the one true God and that admonition is still relevant for Christians today: "Take heed to yourself 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 12:30-31).

Even some Christians who reject religious holidays with roots in paganism, like Christmas and Easter, see nothing wrong with holidays like Valentine's Day, New Year's Day and Halloween despite their pagan origin. The reasoning goes like this: Christmas and Easter must be rejected because they are attempts to worship God with pagan customs. The other holidays, however, while they might have once been used to worship God, are now deemed completely secular. And since what God actually forbids is using pagan customs to worship Him, we are free to practice pagan worship customs if they are not now used for worship.

This reasoning ignores the fact that God told the Israelites to completely eradicate all vestiges of pagan worship. The observance of Valentine's Day is just one of many traditions sincere Christians should avoid, while seeking to return to the foundation of true worship following Jesus Christ as our example.