A brief history of the Valentine tradition in four easy steps:

496AD: Pope Gelasius replaces the Roman festival of Lupercalia with St. Valentine's Day. Well which would you prefer: a giant swingers party or Saintly adoration? (No one knows which Saint Val he was referring to, though. Of the favourites, one sent his still-beating heart to the Czarista that turned him down, as a testament to his undying love/psychosis. It's also the appetizing source of those heart-shaped boxes of chocolate.)

1382: Chaucer makes the first association of seynt Volantynys day /
Whan euery bryd comyth there to chese his make. That's 'chose his mate', by the way, and nothing to do with the cheddar manufacturing industry.

1910: The Hall Brothers is founded by an 18 year old Nebraskan entrepreneur, selling Valentine's and Christmas cards. In 1928 the company adopts the name 'Hallmark', and a legend of trite commercialisation begins in earnest.