Every February 14, lovers from around the world exchange chocolates, flowers and lavish gifts to celebrate the most romantic day of the year: Valentine's Day. But while this popular holiday is now known as a day full of sweet Hallmark cards and romantic dinner ideas for two, did you know there's actually a fascinating — and pretty dark — history of Valentine's Day that dates all the way back to ancient Rome? Here are some facts that may surprise you.

1. St. Valentine wasn't just one person

You may already know that Valentine's Day was named after its patron saint, St. Valentine — but there's actually some confusion surrounding which St. Valentine the holiday technically honors. According to History.com, there are at least two men named Valentine that could've inspired the holiday, including one Valentine who was a priest in third century Rome. As the story goes, this Valentine defied Emperor Claudius II's ban on marriage (he thought it distracted young soldiers), illegally marrying couples in the spirit of love until he was caught and sentenced to death.

Another legend suggests that Valentine was killed for attempting to help Christians escape prison in Rome, and that he actually sent the first "valentine" message himself while imprisoned, writing a letter signed "From your Valentine."

2. Cupid has its roots in Greek mythology

He's the charming cherub that appears on Valentine's Day cards, often depicted with a bow and arrow — but how did Cupid become a common symbol of Valentine's Day? According to Time, the figure can actually be traced all the way back to 700 B.C., to the Greek god of love named Eros, who was actually a handsome, immortal man with the intimidating power to make people fall in love. It wasn't until the 4th century BCE that the Romans adopted Eros into the image of a cute little boy with a bow and arrow, naming him "Cupid." By the turn of the 19th century, Cupid had become linked to Valentine's Day due to his love-matching powers.

3. The first valentine was sent in the 15th century

The oldest record of a valentine being sent, according to History.com, was a poem written by a French medieval duke named Charles to his wife in 1415. Charles penned this sweet note to his lover while he was imprisoned in the Tower of London at just 21 years old. One of the lines in the poem? "I am already sick of love, My very gentle Valentine." Swoon!

4. Not until the 1840s did we get the first mass-produced valentines

People started exchanging cards and handwritten letters to both lovers and friends during the 17th century, but it was in the 1840s that the first Valentine's Day cards were mass-produced in the U.S., sold by Esther A. Howland. Known as the "Mother of the American Valentine," Howland is credited with commercializing Valentine's Day cards in America, and she is remembered for her elaborate, crafty cards made with lace and ribbons.

5. Americans send 145 million Valentine's Day cards each year

According to Hallmark, a whopping 145 million Valentine's Day cards are exchanged every February 14 (and that's not even including all those kids' valentines exchanged in classrooms!). This makes Valentine's Day the second biggest holiday for exchanging greeting cards, after Christmas. And how sweet: Teachers receive the most Valentine's Day cards annually, followed by children, mothers and wives. Needless to say, we've come a long way from 1913, which was when Hallmark Cards produced their first Valentine's card.

6. The Valentine's Day gift that people spend the most on is jewelry

Candy and flowers might be some of the most common gifts for Valentine's Day, but according to the National Retail Federation, the category that we typically spend the most on for February 14 is jewelry, at a whopping $5.8 billion in 2020! The second most-paid-for gift on Valentine's Day 2020 was an evening out with $4.3 billion, followed by clothing, candy and then flowers.

7. The first heart-shaped box of chocolates was introduced in 1861

It was created by Richard Cadbury, son of Cadbury founder John Cadbury, who started packaging chocolates in fancy boxes to increase sales. He introduced the first heart-shaped box of chocolates for V-Day in 1861, and today, more than 36 million heart-shaped boxes of chocolates are sold each year. That's 58 million pounds of chocolate!

8. Nearly 6 million couples get engaged on Valentine's Day

I mean, what better day is there for a marriage proposal than a day literally dedicated to love and romance? Valentine's Day is one of the popular days to pop the question, with as many as 6 million couples getting engaged on February 14. And according to the results of this survey, Valentine's Day was voted the best day of the year to propose than any other day — and of those people who voted, 40% were men!

—Compiled