Nancy Rosin is the president of the National Valentine Collector’s Association and has close to 10,000 pieces in her personal collection. From the first mail-posted Valentine on record in 1806 to some of the precursors to today’s Valentines, her collection is a chronicle of the world’s social history of love.
See the video: http://www.history.com/videos/valentine-cards#valentine-cards
The first recorded association of Valentine’s Day with romantic love is in Parlement of Foules (The Parliament of Birds) (1382) by Geoffrey Chaucer. Chaucer wrote:
For this was on seynt Volantynys day
Whan euery bryd comyth there to chese his make.
[“For this was on Saint Valentine’s Day, when every bird cometh there to choose his mate.”]
This poem was written to honor the first anniversary of the engagement of King Richard II of England to Anne of Bohemia. A treaty providing for a marriage was signed on May 2, 1381. (When they were married eight months later, they were each only 15 years old).
In the period of the English Renaissance Valentine’s Day is mentioned ruefully by Ophelia in Hamlet (1600–1601):
To-morrow is Saint Valentine’s day,
All in the morning betime,
And I a maid at your window,
To be your Valentine.
Then up he rose, and donn’d his clothes,
And dupp’d the chamber-door;
Let in the maid, that out a maid
Never departed more.
—William Shakespeare, Hamlet, Act IV, Scene 5