Conversation so far:
What is the origin of Pierrot?
Pierrot's origins among the Italian players in France are most unambiguously traced to Molière's character, the lovelorn peasant Pierrot, in Don Juan, or The Stone Guest (1665).
Was Pierrot a liked character?
The naive and appealing Pierrot became tremendously popular in French pantomimes.

Question: What play did Pierrot first appear in?
Self-contained rewrite: What French play did Pierrot first appear in?