Apollo et Hyacinthus, K. 38, is an opera written in 1767 by Wolfgang Amadeus Mozart, who was 11 years old at the time. It is Mozart's first true opera (when one considers that Die Schuldigkeit des ersten Gebots is simply a sacred drama). It is in three acts. As is suggested by the name, the opera is based upon the Greek myth of Hyacinth and Apollo as told by Roman poet Ovid in his Metamorphoses. Interpreting this work, Rufinus Widl wrote the libretto in Latin.