Did Shakespeare celebrate St. Patrick’s Day? We really don't know, but you may remember some lines from Hamlet that give us a clue.

You may remember that after Hamlet spoke with his father’s ghost in Act I, Scene 5, he talked with Horatio and Marcellus. Much affected by what he had learned from the ghost, Hamlet spoke with them about his suspicions of villainy in Denmark. Part of their conversation follows –

Horatio. These are but wild and whirling words, my lord.
Hamlet. I’m sorry they offend you, heartily;
Yes, ‘faith heartily.
Horatio. There’s no offence, my lord.
Hamlet. Yes, by Saint Patrick, but there is, Horatio,
And much offence too. 

So, it seems that Shakespeare was familiar with Saint Patrick, and some believe it was because he knew of a cave in Ireland that had become known as St. Patrick’s Purgatory, one of the most important European sites of pilgrimage in Shakespeare’s time. You will remember the words the ghost spoke to Hamlet:

     I am thy father’s spirit, 
     Doom’d for a certain term to walk the night, 
     And for the day confined to fast in fires, 
    Till the foul crimes done in my days of nature 
     Are burnt and purged away. 

So, though Shakespeare may not have celebrated St. Patrick’s Day, we know he was familiar with St. Patrick’s theology! SLÁINTE!SHAMROCK