The period between October 1773 and January 1777 marked Mozart's musical coming-of-age. Behind him were the days on the road, when he traveled with his father and sister from one European capital to the next to wow audiences as a child virtuoso. He was settled back in his hometown of Salzburg, and, barring a three-month visit to Munich, he devoted himself to composing and performing in his capacity as Concertmaster to the Prince-Archbishop of Salzburg. Mozart would only begin his protracted quest to find employment elsewhere in the summer of 1777, finally breaking with Salzburg in 1783. Thus, the Piano Concerto No. 9, composed in January 1777, dates from near the end of this relatively settled period for the young composer, one that found him using the musical forces at his disposal to develop and deepen his style.

The concerto was long known as the "Jeunehomme," an ambiguous reference to the pianist who inspired the work and whose identity the scholar Michael Lorenz has recently confirmed. Her name was Victoire Jenamy (1749-1812), the daughter of the famous 18th-century ballet master Noverre, and she was apparently in Salzburg during the winter of 1776-77. If she was able to play the concerto, she must have been an impressive artist; Mozart took the work with him to show off his own prowess when he went looking for a new job in Mannheim and Paris in 1777-78. It was the first of his piano concertos to appear in print, published in Paris around 1780.

The concerto is in three movements, the standard for classical-era works in the genre. The opening Allegro begins with an original stroke - where listeners would have expected a lengthy orchestral introduction of the movement's themes, Mozart instead prefaces this with a little orchestral flourish answered by an amiable rejoinder from the soloist. In another unexpected stroke, Mozart has the piano intrude on the final moments of the introduction with a long trill. The profundity and play of shade and light in the extraordinary C-minor Andantino contrast sharply with the more carefree atmosphere of the first and third movements. The finale, a rondo, contrasts the opening theme, a spirited sprint by the soloist, with a sequence of episodes, each of them prefaced by a return of this theme. In the middle of the movement, Mozart slows the pace for a gentle minuet episode, with the courtly dance introduced first by the soloist, who then spins out the melody over a pizzicato accompaniment. Knowing what we do now about Mademoiselle Jenamy and her pedigree, the moment becomes yet another example of Mozart's inexhaustible wit.

- John Mangum is the Los Angeles Philharmonic Association's Program Designer/Annotator.