St. Valentine’s Day was first celebrated around 500 AD, but February had been a month associated with romance for more than a thousand years before then.
In ancient Rome, February was the official beginning of spring and was considered a time for purification. People cleaned their houses and said prayers to the pagan gods of fertility. A fertility festival called Lupercalia was held on 15th February every year. The celebration featured a lottery in which young men would each choose the name of a young woman out of a barrel. The young man and woman would become paired for the rest of the year. Couples often ended up marrying.

In 260 AD, Roman Emperor Claudius II outlawed marriage for all young men. He believed that single men made better soldiers than married men and he wanted his army to be as strong as possible. A priest at the time, named Valentine, felt that the law was unfair and continued to perform secret marriage ceremonies for young lovers.
When Claudius found out, he ordered Valentine’s execution. While in prison waiting for his execution, Valentine fell in love with the young daughter of his jailer. Just before his death (on February 14th), he wrote her a love letter which he signed ‘From your Valentine’, an expression still used today.

In 498 AD Pope Gelasius saw his opportunity to replace the pagan festival of Lupercalia with a Christian one. He outlawed Lupercalia and declared 14th February St. Valentine’s Day. So, more than 200 years after Valentine’s death, he became the patron saint of lovers and
St. Valentine’s Day became the date on which lovers all over the world send each other declarations of love.
The oldest valentine message, which still exists, is a poem written by Charles, Duke of Orleans, to his wife during his imprisonment in the Tower of London in 1415. The card can be seen today in the British Museum in London.