The excerpt below is quoted verbatim from:

An Illustrated History of the Rod, by the Reverend William M.Cooper, BA
Wordsworth Editions, London. 1988 pp 39-41
(Originally published at the turn of the last Century.)

*LUPERCAL FESTIVAL EXPLAINED

   "Besides the employment of the whip in the cause of good morals, the Romans introduced whipping into their religious ceremonies, and especially into the festival of the Lupercalia, performed in honor of the god Pan. The word comes from Lupercal, the name of a place under the Palatine Mount, where the sacrifices were performed.

   "The Lupercalia were celebrated on the 15th of the Kalends of March - that is, on the 15th of February, or, as Ovid observes, on the 3rd day after the Ides. They are supposed to have been established by Evander. Virgil speaks of the dancing Salii and naked Luperci, and the commentators explain that these last were men who, upon particular solemnities, used to strip themselves stark naked, and who ran about the streets, carrying straps of goat's leather in their hands, with which they struck such women as they met in their way.

   "Nor did those women run away; on the contrary, they willingly presented the palms jof their hands to them in order to receive the strokes, imagining that these blows, whether applied to their hands or to other parts of their body, had the power of rendering them fruitful or procuring them an easy delivery.

   "The Luperci were in very early times formed into two bands, named after the most distinguished families in Rome, Quintiliani and Fabiani; and to these was afterwards added a third band, named Juliani, from Julius Caesar. Marc Antony did not scruple to run as one of the Luperci, having once harangued the people in that condition. (Ed. note: see Act I, Scene I of Shakespeare's "Julius Caesar.")

  "This feast was established in the time of Augustus, but afterwards restored and continued to the time of Anastasius. The festival was celebrated so late as the year 496 AD, long after the establishment of Christianity. Members of noble families ran for a long time among the Luperci, and a great improvement (!) was moreover made in the ceremony.

   "The ladies, no longer contented with being slapt (sic) on the palms of their hands as formerly, began to strip themselves also, in order to give a fuller scope to the Lupercus, and allow him to display the vigour and agility of his arm. It is wickedly said that the ladies became in time completely fascinated with this kind of "diversion," and that the ceremony being brought to a degree of perfection was so well relished by all parties, that it existed long after many of the other rites of paganism were abolished; and when Pope Gelasius at length put an end to it, he met with so much opposition that he was obliged to write an apology."

*Update from The History Channel excerpted:

   " While some believe that Valentine's Day is celebrated in the middle of February to commemorate the anniversary of Valentine's death or burial — which probably occurred around 270 A.D — others claim that the Christian church may have decided to celebrate Valentine's feast day in the middle of February in an effort to 'christianize' celebrations of the pagan Lupercalia festival.
    "In ancient Rome, February was the official beginning of spring and was considered a time for purification. Houses were ritually cleansed by sweeping them out and then sprinkling salt and a type of wheat called spelt throughout their interiors. Lupercalia, which began at the ides of February, February 15, was a fertility festival dedicated to Faunus, the Roman god of agriculture, as well as to the Roman founders Romulus and Remus."

   "To begin the festival, members of the Luperci ... would gather at the sacred cave where the infants Romulus and Remus, the founders of Rome, were believed to have been cared for by a she-wolf or lupa. The priests would then sacrifice a goat, for fertility, and a dog, for purification. The boys then sliced the goat's hide into strips, dipped them in the sacrificial blood and took to the streets, gently slapping both women and fields of crops with the goathide strips.
   "Far from being fearful, Roman women welcomed being touched with the hides because it was believed the strips would make them more fertile in the coming year.
   "Later in the day, according to legend, all the young women in the city would place their names in a big urn. The city's bachelors would then each choose a name out of the urn and become paired for the year with his chosen woman. These matches often ended in marriage."
   
    "Pope Gelasius declared February 14 St. Valentine's Day around 498 A.D. The Roman 'lottery' system for romantic pairing was deemed un-Christian and outlawed."

www.history.com/content/valentine/history-of-valentine-s-day

########