In 494, Pope Gelasius I banned the pagan festival of Lupercalia and instituted Valentine's Day on 14 February. Some sources suggest that this was done to Christianize the pagan festival Lupercalia which was celebrated on 15 February.

This festival was named after the Lupercal, a cave where they said the Roman founders Romulus and Remus have been suckled and raised by a she-wolf. Lupercalia was a time for matchmaking.

While it’s debated by some modern scholars, it was believed by others that there was a matchmaking lottery associated with the Lupercalia festival. During this time, men would draw women’s names from a hat, and the two would pair up for the duration of the festivities. This would follow suit with some modern-day matchmaking and romantic elements of this holiday. -- Charlotte Wilde

However, Valentine's Day was named after, Saint Valentine, a Christian martyr who was executed around 270 AD. Claudius II had banned marriages and engagements because he believed that married men were not as willing to join the army. Valentine defied Claudius's decree and continued to perform marriages for young lovers in secret. Therefore, Valentine's Day has also been associated with romance. There are many different legends about Saint Valentine, but the most famous one is that he wrote a letter to a blind girl named Julia, who was the daughter of his jailer. In the letter, Valentine expressed his love for Julia and restored her sight. Before he was executed, Valentine signed the letter "From your Valentine." Lupercalia a fertility festival that featured bonfires, sacrifices, and matchmaking.

Valentine's Day did not become associated with romantic love until much later, around the 14th century, influenced by medieval traditions and literature.