He was imprisoned and sentenced to death for his crimes. There, St Valentine apparently fell in love with the jailer's daughter and sent her a love letter signed 'from your Valentine' on February 14th, the day of his execution, as a goodbye.
The name 'Valentinus' is found in the Martyrologium Hieronymianum, a book which was compiled between 460 and 544.
The feast of St Valentine of February 14th was first established in 496 by Pope Gelasius I, who included Valentine among all those "... whose names are justly reverenced among men, but whose acts are known only to God."
Wearing a coronet made from flowers and with a stencilled inscription, St Valentine's skull now resides in the Chiesa di Santa Maria in Cosmedin, on Rome's Piazza Bocca della Verità.
What's Cupid got to do with it all?
Cupid is the god of desire, erotic love, attraction and affection. He is often portrayed as the son of the love goddess Venus and the war god Mars.
Cupid is also known in Latin also as Amor ("Love"). His Greek counterpart is Eros and he is just one of the ancient symbols associated with St Valentine's Day, along with the shape of a heart, doves, and the colours red and pink.
He is usually portrayed as a small winged figure with a bow and arrow which he uses to strike the hearts of people.
People who fall in love are said to be 'struck by Cupid's arrow'.
People born on February 14th
• Frederick Douglass (1818): author and activist, celebrated his birthday on Valentine's Day, not knowing his actual birthdate.
• Lois Maxwell (1927): Actress who played Miss Moneypenny in the James Bond movies.
• Florence Henderson: born in 1934 actress singer best known for her role in the Brady Bunch as Carol Brady.
• Meg Tilly (1960): Actress, dancer, and writer who starred in The Big Chill, Body Snatchers, Valmont and Psycho II and to date has written four novels.
• Carl Bernstein (1944) Washington Post 'Watergate' journalist.
• Kevin Keegan (1951) Ex- European footballer of the year and manager.
• Rob Thomas (1972) Singer, songwriter and is the lead singer of Matchbox 20.
• Mike Bloomberg (1942: ) The 108th mayor of New York City. Recorded as the tenth richest person in the United States with a net worth of $18 billion in 2010.
• Simon Pegg (1970) Actor, comedian, writer, film producer, film director.
When did Valentine's Day become so commercial?
It was during the middle of the 18th century that Valentine's started to take off in England, with lovers sending sweets and cards adorned with flowers, ribbons and images of cupids and birds.
Eventually huge numbers of printed cards replaced hand-written ones. In 1913, Hallmark Cards of Kansas City began mass producing Valentine's cards.
Now about a billion Valentine's Day cards are exchanged every year and it's the second largest seasonal card sending time of the year.
What to write in a Valentine's card
What message will you be writing to your loved one this Valentine's Day?
If you're thinking of just putting "Happy Valentine's Day" and leaving it there - well, that's fine. Not all of us can be poets. But if you wanted to go for something a bit more elaborate, why not take inspiration from some of the greatest love letters ever written?
Alternatively, if you're not a fan of the over-commercialised, Hallmark holiday that is Valentine's Day why not have a look through our gallery of some more cards that prove romance is dead after all.
But why do some people leave anonymous cards?
This trend was started by the Victorians, who thought it was bad luck to sign Valentine's cards with their names.
The Victorians also started the rose-giving trend. They were the favourite flower of Venus, the Roman goddess of love, and have come to indicate passion and romance.
Nowadays, more than 50 million roses are given for Valentine's Day every year.
Every year, there will of course be some people who do not receive any cards, flowers or gifts on Valentine's Day.
One teenager solved that problem by buying 900 carnations and giving them to out to all the girls at his school.
What should you eat on Valentine's Day?
Oysters, a legendary aphrodisiac, are the epitome of Valentine's Day luxury.
Back in the nineteenth century they were the food of the poor, but these days they're been out of reach of all but the most cash-rich Casanovas.
How is Valentine's Day celebrated around the world?
• In parts of Europe lovers give each other St Valentine's keys as romantic gestures and an invitation to unlock the giver's heart.
• In Finland, Valentine's Day is called Ystävänpäivä, which means Friend's Day and focuses on remembering friends.
• However, in Mexico, February 14 is a day of national mourning.
• In countries like Pakistan, Malaysia and Saudi Arabia celebrating the day can result in severe punishment and is seen by conservative Muslims as un-Islamic.
• Japanese Valentine's Day is about all about the men. Women give chocolates to them, and hope favour is returned later in the year.
• In South Korea, February 14 is one of 12 'love' days that fall on the 14th of each month. Women give men presents and they reciprocate on 'White Day' a month later. If the gift isn't returned, singles celebrate White Day by eating jajangmyeon, a dish made from white noodles and black bean sauce.
• In Brazil, Valentine's day isn't celebrated in February because it usually falls on or around Brazil Carnival. Instead, Brazil celebrates 'Dia dos Namorados' on June 12. Brazil's celebration honours Saint Anthony - the patron saint of matchmaking and marriages.
This article originally appeared on the Daily Telegraph.
