St. Valentine was a Roman Priest under Emperor Claudias who persecuted the church and prohibited the marriage of young people. This was based on the hypothesis that unmarried soldiers fought better than married soldiers because married soldiers might be afraid of what might happen to them or their wives or families if they died.
Valentine lived in a very permissive society. Polygamy would have been much more popular than just one woman and one man living together. And yet some of them seemed to be attracted to the Christian faith. But obviously the church thought that marriage was very sacred between one man and one woman for their life and that it was to be encouraged. Valentine secretly married them despite the edict.
Valentine was eventually caught, imprisoned and tortured for performing marriage ceremonies against the command of Emperor Claudius the second. There are legends surrounding Valentine’s actions while in prison.
One of his judges was a man called Asterius, whose daughter was blind. He was supposed to have prayed with and healed the young girl with such astonishing effect that Asterius himself became Christian as a result.
In 269 AD, Valentine was sentenced to a three part execution of a beating, stoning, and finally decapitation all because of his stand for Christian marriage. The story goes that the last words he wrote were in a note to Asterius’ daughter. He signed it, “from your Valentine.” (http://www1.cbn.com/st-valentine-real-story)