The original religious festival takes its name from the Christian saint and martyr Valentine of Terni, and was established in 496 by Pope Gelasius I, replacing the previous pagan festival of Lupercalia . The modern practice of celebrating the holiday, however, centered on the exchange of love messages and gifts between lovers, probably dates back to the early Middle Ages, and could in particular be traced back to Geoffrey Chaucer's circle in which the tradition of love took shape courteous.

The Benedictines contributed to its diffusion, especially in France and England, through their numerous monasteries, having been entrusted with the basilica of San Valentino in Terni from the end of the second half of the 7th century.

Especially in countries of Anglo-Saxon culture, and by imitation elsewhere too, the most characteristic feature of the Valentine's Day celebration is the exchange of valentines , love notes often shaped in the shape of stylized hearts or according to other themes typical of the popular representation of love romantic (the dove, the image of Cupid with bow and arrows, and so on). Since the 19th century, this tradition has fueled the industrial production and large-scale marketing of greeting cards dedicated to this anniversary. The Greeting Card Association has estimated that around one billion greeting cards are sent every year on February 14th, a number which places this anniversary in second place in terms of number of cards purchased and sent, after Christmas. Since the twenty-first century, the feast of Saint Faustino, February 15th, has been considered by some to be the feast of those seeking a soul mate, in contrast to Saint Valentine's Day celebrated the previous day.