"St Valentine was persecuted as a Christian and interrogated by Roman Emperor Claudius II in person. Claudius was impressed by Valentine and had a discussion with him, attempting to get him to convert to Roman paganism in order to save his life. Valentine refused and tried to convert Claudius to Christianity instead. Because of this, he was executed on 14 February c.270. Before his execution, he is reported to have performed a miracle by healing the blind daughter of his jailer.
The Legenda Aurea still providing no connections whatsoever with sentimental love, appropriate lore has been embroidered in modern times to portray Valentine as a priest who refused an unattested law attributed to Roman Emperor Claudius II, allegedly ordering that young men remain single. The Emperor supposedly did this to grow his army, believing that married men did not make for good soldiers. The priest Valentine, however, secretly performed marriage ceremonies for young men. When Claudius found out about this, he had Valentine arrested and thrown in jail.
In an embellishment to The Golden Legend, on the evening before Valentine was to be executed, he wrote the first "valentine" himself, addressed to a young girl variously identified as his beloved, as the jailer's daughter whom he had befriended and healed, or both. It was a note that read "From your Valentine."
In another apparently modern embellishment, while Valentine was imprisoned, people would leave him little notes, folded up and hidden in cracks in the rocks around his cell. He would find them and offer prayers for them.
Of course, there is the more ancient pagan reason: In ancient Rome, February 14 was a holiday to honour Juno. Juno was the Queen of the Roman gods and goddesses. The Romans also knew her as the goddess of women and marriage. The following day, February 15th, began the feast of Lupercalia.
The lives of young boys and girls were strictly separate. However, one of the customs of the young people was name drawing. On the eve of the festival of Lupercalia the names of Roman girls were written on slips of paper and placed into jars. 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 pairing of the children lasted an entire year, and often, they would fall in love and would later marry."