For this was on seynt Volantynys day Whan euery bryd comyth there to chese his make.
February is a little early for birds to be choosing their mates, and it's thought that Chaucer was referring to a date in May when the second saint Valentine (there were two of them) had his feast day. No matter, the winter tradition took hold, and Valentine's Day endured, a burning ember from the fire of courtly love. The earliest surviving valentine was sent from the Tower of London in 1415 by the imprisoned Duke of Orleans to his wife.
Brits carried their customs around the world, or mailed them. Around 1847 Esther Howland received a valentine from a British admirer. Her father owned a large stationery store in Worcester, Massachusetts, and within a year Esther was producing valentines of embossed paper lace and selling them in America.
The bow of commerce has been shooting the arrows of love ever since. Happy Valentine's Day.