Valentine's Day started during the Roman Empire. Under the rule of Emperor Claudius II, Rome was involved in many bloody military campaigns. Claudius the Cruel, as he was known at the time, was having difficulty in getting soldiers to join his military leagues. He believed that the reason was that Roman men did not want to leave their lovers or families. As a result, Claudius cancelled all marriages and engagements in Rome.
A Christian priest named Valentine came to defend love in the empire. Valentine began to secretly marry couples despite the emperor's orders. When Emperor Claudius was informed of these ceremonies, Valentine was sent to prison where he remained until his death on February 14 in the year 270.
It wasn't until a few hundred years later when Valentine's Day began to develop as we know it. At that time Christianity was beginning to take control of Europe.
In honor of his sacrifice for love, Valentine was made a saint. And as part of the effort the Church was making to do away with pagan holidays, Valentine's Day came to replace a mid-February fertility festival called Lupercalia.
Today the tradition of honoring St. Valentine continues. The themes of love and fertility taken from the ancient meanings of the holiday have endured and evolved through time.