When the music is Mozart’s, and the conversation is sublime

Where to begin with Mozart? Why not start at the top, with the Sinfonia Concertante.

Mozart places the solo violin and a solo viola in searching, wistful dialogue.Maura Intemann/

There are, to be sure, more famous or popular on-ramps. There is the “Turkish March,” responsible for many an earworm. There is “Eine Kleine Nachtmusik,” known from countless commercials. And there is the dazzling Queen of the Night aria, in which the human voice dances at vertigo-inducing heights.

But if your goal is to develop not a passing fancy but rather a deep and abiding love of Mozart’s music — or to feed an affection already instilled — I can think of few better places to start than the Sinfonia Concertante in E-flat, K. 364. This three-movement score, to be performed by Boston Baroque on March 25 and 26, is at once an insider’s masterwork and, for newcomers, a delightfully lucid point of entry into the infectious joy, the wistful beauty, and the glowing sadness of Mozart’s world.

The work’s uniqueness begins with its instrumentation — it is essentially a double concerto with the solo violin and, crucially, the solo viola accompanied by an orchestra. Pitched one-fifth beneath the violin, and lacking its brilliant E-string, the viola would not really come into its own as a solo instrument until the 20th century — but here it is on visionary display in a score probably written in 1779.

With its midrange amber warmth and its position near the heart of any chord, the viola was Mozart’s favorite instrument to play in chamber music settings. It has also been speculated that he may have written this solo viola part with the intention of playing it himself. Whatever the case, the instrument’s mellow spirit and wise timbre permeates this score. The scholar Charles Rosen has gone as far as describing the work’s “characteristic sound” as “the sonority of the viola translated into the language of the full orchestra.”

But more than simply offering a unique sound world, the Sinfonia Concertante is an exquisite study of two instrumental voices in relationship. That’s a word you might not associate with the concerto genre, more commonly connected with virtuosic display. Indeed Mozart’s own five violin concertos (already in the rear view mirror by the time he came to write this piece) furnish soloists with plenty of material with which to amuse and impress the ear. Even other double concertos — such as, most famously, the Brahms Double, for violin and cello — do not really challenge that conception but rather, at least in the case of the Brahms, thrillingly double down on it.

But in Mozart’s work the solo lines are constantly in conversation. The first movement is full of both thoughtful dialogue and witty banter between violin and viola, imitative lines dispatched at times with playful one-upmanship. That pervasive dialogue, however, also means that one-half of each soloist’s performance is listening. The act of hearing an “other” is written into the music itself. In fact the two soloists’ fundamental sense of common cause, their unity of purpose, is established from their very first shared entrance, a simple E-flat held in perfect octaves for a sublime eight beats.

The work’s outer movements are both high-spirited excursions, the first with a grander public bearing, the last with a lightly tripping, carefree air. But the work’s central slow movement stands as the piece’s sad and noble heart, an ineffably beautiful series of solo lines laden with an unnamed yet unmistakable grief, leavened only slightly by a sense of reluctant acceptance.

The orchestra here accompanies the soloists with empathy and care, until one point near the end of the movement, when the ensemble recedes into silence. It’s as if the well-wishing crowd has drifted away, the community has gone home, and the two mourners, having maintained their dignified composure in public, are now left to speak only with each other. For this moment, Mozart supplies a through-written double cadenza, 18 bars of time-stopping music that must be among the most soulful, poignant passages he ever composed.

The piece has been recorded countless times. Among my personal favorites are the father-son accounts of David and Igor Oistrakh, one of which, a performance conducted by Yehudi Menuhin, can be found on YouTube. Oistrakh père was a sovereign violinist, one of the greatest of the 20th century. But here, with a touching humility, a graceful gesture of parental deferral, he steps aside, allowing his son the privilege of playing the violin part, and taking up the viola lines himself with incomparable dignity and warmth.

In their hands the piece becomes a dialogue between generations across time, or one might say, becomes such a dialogue again. Mozart’s own complex relationship with his father, a violinist and pedagogue, hovers somewhere in the background behind all of these notes. As with all great works of art, there are layers within layers here — and a reservoir of meaning deep enough to last a lifetime.