Valentine's Day and Ash Wednesday were on the same day this year. This caused some confusion, as to which holiday Catholics should celebrate. Answer: Ash Wednesday, the more important one.
The weird thing is, Catholics haven't celebrated Saint Valentine's Day in 50 years. In the 1960's, the Catholic Church updated its calendar, to remove any questionable saints. You know, people who might not have existed, whose stories are just legends or myths. Saint Valentine was removed, as part of that purge.
Saint Valentine definitely existed, though, and he was kept on the official list of martyrs. He was killed in the 200's, and we know where he was buried. That's about all the historians can agree on. There's disagreement as to how and why he died, although most people agree he was beheaded for trying to convert the emperor.
I know there's a cute story about Saint Valentine helping two people find love. Some people say the legend is why he's associated with romantic love, while other people think the legend was invented after the fact, to justify the association. Sounds like a "chicken and the egg" problem historians won't be able to solve, without new evidence.