This holiday first started out in Ancient Greece (hint: Cupid's arrow) as Lupercalia and the feast day of Juno Februata.
Celebrated February 15, The holiday Lupercalia (also known as the festival of sexual licence) Was made to hold remembrance to the Pagan god Lupercus, god of fertility and husbandry, protector of herds and crops, and takes the image of a wolf. She was believed to protect the People from famine and keep wolves from invading and destroying crops as well as killing people.
Assisted by Vestal Virgins, the Luperci (male priests) conducted purification rites by sacrificing goats and a dog in the Lupercal cave on Palatine Hill, where the Romans believed the twins Romulus and Remus had been sheltered and nursed by a she-wolf before they eventually founded Rome. Clothed in loincloths made from sacrificed goats and smeared in their blood, the Luperci would run about Rome, striking women with februa, thongs made from skins of the sacrificed goats. The Luperci believed that the floggings purified women and guaranteed their fertility and ease of childbirth
fun fact: February derives from februa or “means of purification.”
To the Romans, February was also sacred to Juno Februata, the goddess of febris (“fever”) of love, and of women and marriage. On February 14, billets (small pieces of paper, each of which had the name of a teen-aged girl written on it) were put into a container. Teen-aged boys would then choose one billet at random. The boy and the girl whose name was drawn would become a “couple,” joining in erotic games at feasts and parties celebrated throughout Rome the next day.
After the festival, they would remain sexual partners for the rest of the year.
In A.D. 494, Pope Gelasius renamed the festival of Juno Februata as the “Feast of the Purification of the Virgin Mary.” The date of its observance was later changed from February 14 to February 2, then changed back to the 14. It was also known as "Candlemas", the Presentation of the Lord, the Purification of the Blessed Virgin and the Feast of the Presentation of Christ in the Temple.
After Constantine had made the Roman church’s brand of Christianity the official religion of the Roman Empire (A.D. 325), church leaders wanted to do away with the pagan festivals of the people. Lupercalia was high on their list. But the Roman citizens thought otherwise. It was not until A.D. 496 that the church at Rome was able to do anything about Lupercalia. Powerless to get rid of it, Pope Gelasius instead changed it from February 15 to the 14th and called it St. Valentine’s Day. It was named after one of that church’s saints, who, in A.D. 270, was executed by the emperor for his beliefs.
According to the Catholic Encyclopedia, “At least three different Saint Valentines, all of them martyrs, are mentioned in early martyrologies under the date of 14 February. One is described as a priest at Rome, another as bishop of Interamna (modern Terni), Of the third Saint Valentine, who suffered in Africa with a number of companions, nothing is further known.” Several biographies of different men named Valentine were merged into one “official” St. Valentine.
The church changed Lupercalia even further to make it more acceptable among the culture. Instead of putting the names of girls into a box, the names of “saints” were drawn by both boys and girls. It was then each person’s duty to emulate the life of the saint whose name he or she had drawn. This was Rome’s attempt to change the pagan observance by Christianizing and making it more acceptable according to the church. Though the church at Rome had banned the sexual lottery, young men still practiced a much toned-down version, sending women whom they desired handwritten romantic messages containing St. Valentine’s name. (that's how we get the cards today)
Over the centuries, St. Valentine’s Day cards became popular, especially by the late eighteenth and early nineteenth centuries. These cards were painted with pictures of Cupid and hearts, and meticulously decorated with lace, silk or flowers. (or in this case, Humanized cats with punching pillows)