It is almost impossible to write a definitive history of Valentine's Day because most of it is lost. What we do know is a strange mix of religious facts and historical legends.
Saint Valentine's
The Catholic Church recognizes seven Saint Valentines. The first Valentine was a priest in third-century Rome. He would marry young couples, although the emperor had outlawed marriage for anyone under a specific age. When caught, the emperor executed him. Another Valentine was the Bishop of Interamna. Imprisoned for helping Christians escape from Roman persecution, legend says he fell in love with the daughter of his jailor. His last act was to send her a letter expressing his love, signed "From Your Valentine."
There is still another Saint Valentine associated with Feb. 14. According to the Catholic Church, this Valentine was martyred in Africa, but nothing else is known about him. Some scholars even speculate that this Valentine and one or both of the first two are the same person. It is also important to note that in the earliest saint biographies, Valentine had nothing to do with romantic love. It wasn't until the 14th century that writers such as Geoffrey Chaucer linked Saint Valentine, springtime with and romantic love.
Lupercalia
Some people say we celebrate Valentine's Day in February to mark the date of St. Valentine's birth or death. Others, hypothesize that the holiday is a way to Christianize pagan fertility rituals. The ancient Romans observed Lupercalia between Feb. 13 and 15, the start of spring in the Roman calendar. Rituals included warding off evil spirits and sanctifying the city, releasing health and fertility. Citizens swept out their houses and blessed them with a mixture of salt and wheat.
But, Lupercalia had no romantic overtones to it, unlike the Festival of Juno Februa, which took place Feb. 14. Roman priests would sacrifice a goat then skin it. Cutting the skin into strips and dipping them in the sacrificial blood. The priest would then take the strips into the street to gently slap women. To be touched by the strip was a blessing of fertility for women and crops. Later in the festival, the young women would place their names in an urn, and the city bachelors would select a name from the urn to be paired with for the festival, hopefully to end in marriage. The pope outlawed both rituals, but the masses still practiced them.
Commercialization
As Chaucer's idea of Valentine's Day romance became more popular, people began exchanging notes and cards. The modern holiday of Valentine's Day is celebrated in the United States, Canada, Mexico, France, United Kingdom and Australia.