Which St. Valentine this early pope intended to honor remains a mystery: according to the Catholic Encyclopedia, there were at least three early Christian saints by that name. One was a priest in Rome, another a bishop in Terni, and of a third St. Valentine almost nothing is known except that he met his end in Africa. Rather astonishingly, all three Valentines were said to have been martyred on Feb. 14.
Most scholars believe that the St. Valentine of the holiday was a priest who attracted the disfavor of Roman emperor Claudius II around 270. At this stage, the factual ends and the mythic begins. According to one legend, Claudius II had prohibited marriage for young men, claiming that bachelors made better soldiers. Valentine continued to secretly perform marriage ceremonies but was eventually apprehended by the Romans and put to death. Another legend has it that Valentine, imprisoned by Claudius, fell in love with the daughter of his jailer. Before he was executed, he allegedly sent her a letter signed "from your Valentine." Probably the most plausible story surrounding St. Valentine is one not focused on Eros (passionate love) but on agape (Christian love): he was martyred for refusing to renounce his religion.
In 1969, the Catholic Church revised its liturgical calendar, removing the feast days of saints whose historical origins were questionable. St. Valentine was one of the casualties.
Read more: Valentine's Day History http://www.infoplease.com/spot/valentinesdayhistory.html#ixzz3a4iG1lEL