as in hamlet

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)