The original religious holiday 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 be traced back in particular to the circle of Geoffrey Chaucer in which the tradition of courtly love took shape.

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 Anglo-Saxon countries, and by imitation elsewhere, the most characteristic feature of the feast of Saint Valentine is the exchange of valentines , love notes often shaped in the form of stylized hearts or according to other themes typical of the popular representation of romantic love (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 holiday. The Greeting Card Association has estimated that every year on February 14th about a billion greeting cards are sent, a number that places this holiday in second place, in terms of number of cards purchased and sent, after Christmas. Since the twenty-first century, the feast of Saint Faustino, on February 15th, has been considered by some to be the holiday of those looking for their soul mate, precisely in contrast to Saint Valentine's Day celebrated the day before.