Take an online quiz to test your skill at identifying the two composers:
The two were contemporaries, friends, colleagues, and mutual admirers. Can you tell if a piece is by Mozart or Haydn? Fred Child tests your Mozart meter by administering a good-natured quiz.
Joseph Haydn in a detail from a 1792 painting by Thomas Hardy.
Commentator Rob Kapilow has his own ideas of what makes Haydn different from Mozart.
And we hear Mozart's own letter he wrote to Haydn along with the set of string quartets he dedicated to his mentor.
The Fine Arts Quartet plays one of Mozart's "Haydn" Quartets, K. 464, in La Jolla, Calif.