During the feast, single women would place their names in a
large bowl with each single male drawing one name. The men would be
that woman's partner for the festival. Sometimes the couple would
fall in love, and there would be no reason to enter the drawing
next year.
It is possible that the feast of Lupercalia was combined with the
February 14 feast for Juno, the Roman goddess of women and
marriage, and moved back to the day of the anniversary of the
martyrdom of St. Valentine.
But what about the tradition of exchanging cards and gifts on
Valentine's Day? Did that start with the Roman women writing their
names down and giving them to the men? Or did the tradition
originate with the story about the second Valentine, who was said
to be a prolific writer who exchanged several dozen letters while
imprisoned?
Most likely, it was Geoffrey Chaucer, author of The Canterbury
Tales.