Saint Valentine is a Third-Century Roman saint whose feast day is February 14th. Little is known about him except that since the late Middle Ages he has been associated with courtly love. A saint with the same name was martyred and buried on February 14th in Rome. It is also possible that two saints are represented by the same name.
So little is known about Saint Valentine that in 1969 the Roman Catholic Church removed his name from their Roman Calendar and left it to the local dioces to decide whether or not to commemorate Saint Valentine on his feast day.
Either way, though, today Saint Valentine is considered unofficially to be the saint of romantic love everywhere.