Valentine Day By St. Valentine

Valentine Day February 14 became the date for exchanging love messages and St. Valentine became the patron saint of lovers. The date was marked by sending poems and simple gifts such as flowers.
The day is most closely associated with the mutual exchange of love notes in the form of "valentines".

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)