This saint's feastday is well known far beyond the Catholic Church because of its association with lovers. Cards, gifts, and romantic dinners are timed in his honor.
Surprisingly, not that much is known about St. Valentine. He was a priest in Italy and was martryed in 269 outside Rome along the Flaminian Way. A basilica was built there in 350, but a church under his patronage already existed in Interamna (Terni). He may have been bishop there. His relics were transferred in the ninth century to Rome's church of St. Praxedes.
There are two main theories why Valentine is linked to lovers. In the 14th century, First, Geoffrey Chaucer wrote a poem suggesting that birds choose their mates on February 14. Second, at the pagan festival of Lupercalia (February 15), names of young men and young women were drawn at random. The feast of St. Valentine may be a Christianized version of this—but now not for random pairings!