What is the origin of Valentine’s Day, and should Christians celebrate it?

The first Valentine was posted around 1806. Almost one billion
Valentine's Day cards are sent each year on or near February 14 with
females purchasing 85% of the cards. This is second only to the number
of Christmas cards sent. The history is somewhat murky as to how
Valentine's Day has come to be what we now know and celebrate. Saint
Valentine served in third-century Rome. Emperor Claudius decided that
single men made better soldiers. Therefore, Claudius banned soldiers
from being married. One version of the story is that Valentine
continued to perform the weddings of young soldiers who were in love,
and Claudius had Valentine imprisoned. While imprisoned, Valentine
reportedly fell in love with the jailer's daughter. Valentine sent her
a card and signed it, "Love, your Valentine." Another version is that
Valentine defied Claudius by helping Christians escape the torture of
the Romans.

Valentine died in approximately A.D. 270. Others claim the church may
have decided to celebrate in mid February to "Christianize" the pagan
Roman celebration Lupercalia. The first Valentine sent in the United
States was in the 1840's by Esther Howgald. Most of us enjoy
"spoiling" a loved one on Valentine's Day. Sending gifts and cards
conveys love, affection, and friendship.

There is no biblical reason why Christians should not celebrate
Valentine's Day by giving their loved ones flowers, candy and/or
cards. As with celebrating any holiday, the decision should be between
the individual and God. Some people feel very strongly that observing
any secular holiday is wrong, while others see it as harmless. The
important thing to remember is that celebrating or not celebrating
holidays should not be a cause for pride or division among Christians.