When did it all start?
There are various theories on the origin of Valentine's Day, but the most popular dates back to the time of the Roman Empire during the reign of Claudius II, 270 AD. Claudius didn't want men to marry during wartime because he believed single men made better soldiers. Bishop Valentine went against his wishes and performed secret wedding ceremonies. For this, Valentine was jailed and then executed by order of the Emperor on February 14. While in jail, he wrote a love note to the jailor's daughter signing it, "From your Valentine."Sound familiar?

More Valentine's Day-related History
•The ancient Romans celebrated the Feast of Lupercalia on February 14th in honor of Juno, the queen of the Roman gods and goddesses. Juno was also the goddess of women and marriage.
•Many believe the 'X' symbol became synonymous with the kiss in medieval times. People who couldn't write their names signed in front of a witness with an 'X.' The 'X' was then kissed to show their sincerity.
 •In the Middle Ages, young men and women drew names from a bowl to see who would be their Valentine. They would wear this name pinned onto their sleeves for one week for everyone to see. This was the origin of the expression "to wear your heart on your sleeve."
 •In 1537, England's King Henry VII officially declared February 14th the holiday of St. Valentine's Day.
Chocolate
•Physicians of the 1800's commonly advised their patients to eat chocolate to calm their pining for lost love.
•Richard Cadbury produced the first box of chocolates for Valentine's Day in the late 1800's.
•More than 35 million heart-shaped boxes of chocolate will be sold for Valentine's Day.
 •Over $1 billion worth of chocolate is purchased for Valentine's Day in the U.S.
Flowers
 •73% of people who buy flowers for Valentine's Day are men, while only 27 percent are women.
 •15% of U.S. women send themselves flowers on Valentine's Day.
Roses
 •The red rose was the favorite flower of Venus, the Roman goddess of love.
•Red roses are considered the flower of love because the color red stands for strong romantic feelings.
•189 million stems of roses are sold in the U.S. on Valentine's Day.
•California produces 60 percent of American roses, but the greater number sold on Valentine's Day in the United States are imported, mostly from South America.
 •Approximately 110 million roses, mostly red, will be sold and delivered within the three-day Valentine's Day time period.“145 million Valentines are sent out in the U.S. each year.„
Greeting Cards
 •Approximately 145 million Valentines are sent out in the U.S. each year according to estimates by the U.S. Greeting Card Association. That's second only to Christmas with 1.6 billion units, and is followed by Mother's Day with 133 million units.
 •Women purchase approximately 85 percent of all Valentines.
 •Over 50% of all Valentine's Day cards are purchased in the six days prior to the holiday, making Valentine's Day a procrastinator's delight.
•Teachers will receive the most Valentine's Day cards, followed by children, mothers, wives, sweethearts and pets.

More fun facts about Valentine's Day
•In addition to the United States, Valentine's Day is celebrated in Canada, Mexico, United Kingdom, France, Australia, Denmark, and Italy.
•The most fantastic gift of love is the Taj Mahal in India. It was built by Mughal Emperor Shahjahan as a memorial to his wife.
•In the 1800s doctors commonly advised their heartbroken patients to eat chocolate, claiming it would sooth their pain. To this day, many women find comfort in a box of chocolates when dealing with heartbreak.
 •A love knot is a symbol of undying love, as it's twisting loops have no beginning and no end. In olden times they were mad of ribbon or drawn on paper to prove one's eternal love.
 •Every Valentine's Day, the Italian city of Verona, where Shakespeare's lovers Romeo and Juliet lived, receives about 1,000 letters addressed to Juliet.
 •About 3% of pet owners will give Valentine's Day gifts to their pets.
 •220,000 is the average number of wedding proposals on Valentine's Day each year.
 •In the US, 64 percent of men do not make plans in advance for a romantic Valentine's Day with their sweethearts. Share these fun facts about Valentine's Day with a friend. Your sweetie might be especially nterested in the last item. Happy Valentine's Day!

http://www.sheknows.com/holidays-and-seasons/articles/807655/fun-facts-about-valentine-s-day