This anniversary year of Mozart offers a great opportunity to retrace the maestro's musical growth and development, and here's a good place to start: Apollo et Hyacinthus (Köchel 38), written when he was just 11 years old. Though it's being produced as a full-blown opera, technically the piece is an intermedio, a short musical drama originally staged during intermissions of a larger, more serious work.

The larger work in this case was Clementia Croesi, a forgettable tragedy written by Benedictine monk and syntax professor Rufinus Widl for the May 1767 graduation ceremonies of the grammar school of Benedictine University in Salzburg. As a breaker, Widl also penned Apollo et Hyacinthus, his version of a well-known Greek myth taken from Ovid's Metamorphoses.

The young Mozart was already a star, having just returned to Salzburg from a three-and-a-half-year tour of Europe that left royal courts buzzing. "Little Wolfgang" and his sister Marianne were billed as child prodigies, and, as his father Leopold wrote — with apparently little exaggeration — "Everyone is amazed, especially at the boy, and everyone whom I have heard says that his genius is incomprehensible."

Young Mozart had impressed not only as a performer but as a composer, already showing considerable versatility and skill in handling symphonies, sonatas, sacred music and an oratorio. Apollo was one of several important composing assignments he was given upon his return to Salzburg. To link and embellish Widl's recitative, Mozart wrote five arias, two duets, a chorus and a trio. (For this production, his Symphony No. 1 in E-flat, written in 1764, is being used for the overture and intermezzos.)

The basic story of Apollo and Hyacinth is simple: The god Apollo has a mortal boyfriend, a beautiful youth named Hyacinth. But Zephyr, the west wind, loves Apollo and is jealous. One day, while Apollo and Hyacinth are throwing around the discus, Zephyr blows it off-course so that it hits Hyacinth in the head and kills him. Grief-stricken, Apollo turns his dying companion into a beautiful flower.

The drama is a bit more complicated. Since a Catholic university couldn't stage a homosexual love story, Widl added a female love interest, Melia, the daughter of King Oebalus. Hyacinth is his son. When Apollo asks for Melia's hand in marriage, Zephyr, who also loves Melia, causes the tragic disc accident and then tries to blame Apollo. The gambit works temporarily, but after the usual mix-ups and recriminations, Apollo dispatches Zephyr by turning him into a breeze, wins Melia's hand and turns Hyacinth into a gorgeous bed of flowers.

Real opera or not, Apollo is a startling accomplishment for an 11-year-old. In particular, music critics cite Mozart's precocious ability to crystallize emotions and dramatic tension in music, and single out a couple moments that show a marked maturity. Apparently undaunted by the fact that all the parts in the original production would have been sung by teenage boys, he wrote a richly emotional aria in the second act for Melia, rejoicing at her prospective future as the wife of a god. And the death of Hyacinth and subsequent grieving of Melia and Oebalus that open the third act are remarkably sophisticated.

The very first audience to hear Apollo was impressed as well. "The music for it, composed by Wolfgang Mozart, delighted everybody," one observer wrote. "And at night he gave us notable proofs of his musical art at the harpsichord."