Valentine's Day derives from a Christianized version of a pagan holiday called Lupercalia.
The name "Valentine" comes from one of two Christian martyrs of the 3rd century. One describes a Roman Christian martyred during the persecution of Claudis II, the other, a bishop of Terni who was martyred in Rome.
There occurs several versions of the Christian legend but no one knows the truth for sure. But the celebration of giving notes and gifts to loved ones began long before the Christian version and no doubts exist about its historical practice.
Lupercalia was a very ancient, pre-Roman pastoral festival, observed on February 13 through 15 to avert evil spirits and purify the city, releasing health and fertility. Lupercalia subsumed Februa, an earlier-origin spring cleansing ritual held on the same date, which gives the month of February (Februarius) its name.
The Lupercalia festival was partly in honor of Lupa, the she-wolf who suckled the infant orphans, Romulus and Remus, the founders of Rome, explaining the name of the festival, Lupercalia, or “Wolf Festival.” The festival was celebrated near the cave of Lupercal on the Palatine Hill (the central hill where Rome was traditionally founded), to expiate and purify new life in the Spring.
The 14th of February was the day specially set aside for love lotteries in Pagan Rome. A holiday devoted to Juno, Queen of the Gods, and patroness of marriage, the 14th was also the day on which young girls' names were written on slips of paper and thrown into jars to be picked out by the boys. Chooser and chosen would then be partnered for the duration of the Lupercalia festival. Such arbitrary pairings often resulted in lasting relationships. The Catholic Church later substituted the names of dead saints in place of those of flesh-and-blood girls to subvert the lusty Pagan practice.
The festival began with the sacrifice by the Luperci (or the flamen dialis) of two male goats and a dog; after which two of the Luperci were led to the altar, their foreheads were touched with a bloody knife, and the blood wiped off with wool dipped in milk; then the ritual required that the two young men should laugh. The smearing of the forehead with blood probably refers to human sacrifice originally practised at the festival.
The sacrificial feast followed, after which the Luperci cut thongs from the skins of the victims, which were called februa, dressed themselves in the skins of the sacrificed goats, in imitation of Lupercus, and ran round the walls of the old Palatine city, the line of which was marked with stones, striking the people who crowded near. Girls and young women would line up on their route to receive lashes from these whips. This was supposed to ensure fertility, prevent sterility in women and ease the pains of childbirth. These thongs were called februa, the festival Februatio, and the day dies febraiatus (februare = to purify); hence the name of the month February, the last of the old Roman year. The object of the festival was, by expiation and purification, to secure the fruitfulness of the land, the increase of the flocks and the prosperity of the whole people.
Archaeological evidence suggests that the Lupercalia, far from being restricted to Rome, was practised in other cities in Italy and Gaul.
Dating from remotest antiquity, the Lupercalia was celebrated until as late as the reign of Anastasius I in 491-518 CE. It was towards the end of the 5th century in 498 CE that Pope Galesius decided to dedicate the Eve of Lupercalia to the long-dead priest. The lottery system was banned as being un-Christian and the Pope did his best to make people forget about other un-Christian ideas such as fertility.
However, the Pagan principles of the people proved irrepressible. Memories of the Roman Lupercalia combined with folklore beliefs in Britain and France that the 14th of February marked the beginning of the mating season amongst birds to ensure that this day would persist in the popular imagination as a day of love.
The oldest extant Valentine message is a poem written by Charles, Duke of Orleans, in 1415 to his wife. He had good reason to write: he was imprisoned in the Tower of London after being captured at the Battle of Agincourt. It proved a popular idea and some years later it is believed that Henry V hired John Lydgate to compose a Valentine missive to Catherine of Valois.
Despite such early precedents, St Valentine's Day did not become a widely celebrated event in Britain until the 17th century. Printed cards did not appear until the late 18th century, but it was not until the 1840's that Esther A. Howland entered the history books as the first person to sell the first mass-produced Valentine cards in the United States.