This section is from the book "A Library Of Wonders And Curiosities Found In Nature And Art, Science And Literature", by I. Platt. Also available from Amazon: A library of wonders and curiosities.
Valentine was a pope, or bishop of Rome, that lived in the ninth century; who, on this day, established an annual custom of the poorer clergy drawing patrons by lots for the commenced year; and these patrons, or benefactors, were called Valentines. After his death he was canonized for a saint, and his feast-day kept on the fourteenth day of February, which was thought to be his birth-day. Mr John Gordon, in his memoirs and account of the popes, says, "that Valentine was too good a man to be a good pope, and died forty days after his consecration, or instalment; being choked with a fish-bone."
This custom, in Britain, evidently appears to have been copied by the laity from the clergy, in the days of popery, and is a very ancient custom, being almost of a thousand years standing. The birds too are supposed to choose their mates, and pair, on this day; which, no doubt, is an additional reason to our youth of both sexes who are approaching to maturity, to write their verses, and with much ingenuity ply scissars, pen, and pencil, in honour of their selected or allotted lovers.
 
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