Valentine's Day started in the time of the Roman Empire. In ancient Rome, February 14^th was a holiday to honor Juno. Juno was the Queen of the Roman Gods and Goddesses1. The Romans also knew her as the Goddess of women and marriage. The following day, February 15^th, began the Feast2 of Lupercalia.
   The lives of young boys and girls were strictly separate. However, one of the customs of the young people was name drawing3. On the eve of the festival of Lupercalia the names of Roman girls were written on slips4 of paper and placed into jars5. Each young man would draw a girl's name from the jar and would then be partners for the duration of the festival with the girl whom he chose. Sometimes the pairing6 of the children lasted an entire year, and often, they would fall in love7 and would later marry.
   Under the rule8 of Emperor Claudius II Rome was involved in many bloody9 and unpopular campaigns. Claudius the Cruel10 was having a difficult time getting soldiers to join his military leagues11. He believed that the reason was that roman men did not want to leave their loves12 or families. As a result, Claudius cancelled all marriages and engagements13 in Rome. The good Saint Valentine was a priest at Rome in the days of Claudius II. He and Saint Marius aided the Christian14 martyrs15 and secretly married couples, and for this kind deed16 Saint Valentine was apprehended17 and dragged18 before the Prefect of Rome, who condemned him to be beaten19 to death with clubs20 and to have his head cut off. He suffered martyrdom21 on the 14^th day of February, about the year 270. At that time it was the custom in Rome, a very ancient custom, indeed, to celebrate in the month of February the Lupercalia, feasts in honor of a heathen22 god. On these occasions, amidst a variety of pagan ceremonies, the names of young women were placed in a box, from which they were drawn by the men as chance directed.
   The pastors of the early Christian Church in Rome endeavored23 to do away with the pagan element in these feasts by substituting the names of saints for those of maidens24. And as the Lupercalia began about the middle of February, the pastors appear to have chosen Saint Valentine's Day for the celebration of this new feast. So it seems that the custom of young men choosing maidens for valentines25, or saints as patrons for the coming year, arose in this way.

theindependent.com