90% sureThese words were traced back to where they first appeared. That source is listed below.
What turned up
William Shakespeare, Hamlet, Act 1, Scene 3 (Polonius to Laertes): 'This above all: to thine own self be true.' Written c. 1600-1601, first printed 1603. Verbatim Shakespeare — not an anonymous proverb.
Work
Hamlet, Act 1, Scene 3
Occasion
c. 1600 · Polonius's parting advice to his son Laertes
Sources checked
folger.eduChecked using claude-sonnet-5, 21 August 2026Folger Shakespeare Library text of Hamlet Act 1 Scene 3, confirms speaker and surrounding lines
Second edition text (MIT Complete Works) — 'This above all: to thine ownself be true' confirmed by direct fetch; the Folger citation from intake was also re-fetched and confirmed this pass
Nothing made from these words yet — Storyfaire is where they get made.
The quality of mercy is not strain'd, it droppeth as the gentle rain from heaven.William Shakespeare
