Conversation so far:
What is notable about Harpo Marx on stage?
In January 1910, Harpo joined two of his brothers, Julius (later Groucho) and Milton (later Gummo), to form The Three Nightingales, later changed to simply The Marx Brothers.
What is Harpo Marx' stage name?
Harpo

Question: Did he perform any other acts on stage?
Self-contained rewrite: Did Harpo Marx perform any other acts on stage?