Osvaldo Golijov appeared on Monday night to offer his newest orchestral composition to the Tanglewood Music Center Orchestra. This was one of several dozen new works commissioned this summer for the 75^th anniversary of the Music Center. Golijov has had an ongoing connection with the Boston Symphony Orchestra since he was a Tanglewood fellow in the summer of 1990. He is currently at work on a full-scale opera based on Euripides’ Iphigenia in Tauris, to be performed at the Metropolitan Opera.

Although he had first intended to write simply a fanfare-like “post card” of musical celebration for the anniversary, he produced instead a score running about 13 minutes for string orchestra and solo horn, working with musical ideas conceived as possible music for the character Clytemnestra in his unfinished opera. But the imagery that he attaches to it in this score is not from classical Greece, but rather from the Bible: the monster Leviathan, referred to in Genesis, Jonah, and Job to represent a figure opposite to that of God.

The new work is entitled Sign of the Leviathan; the string orchestra evidently represents the waves of the sea and its mysterious depths, while the challenging solo horn part is a stand-in for the Leviathan.

As often happens with Golijov, final details of the work were still being completed at a late stage. At the composer’s request, the performance was conducted by Stefan Asbury, who had been a Tanglewood conducting fellow the same summer the Golijov was a composition fellow, and who is now in charge of the conducting program at Tanglewood.

The sound of the string orchestra was both varied and, in a sense, monotonous, like the surface of the sea, always active with its wave motion and feeling of surging depth, but not changing substantially. The horn solo, conceived for BSO principal horn James Sommerville, made exceptional demands in extremes of range, sustained long notes, and dynamics. The composer explained in a conversation immediately before the performance that he had been specifically inspired by hearing Sommerville’s performance with the Boston Symphony in the Mahler’s Sixth Symphony last season. A particular horn figure, consisting of a high note moving down an octave connected by a portamento, became a significant motif of the new score, both moving from high to low and in the opposite direction.

Frankly, at a first hearing, I found it difficult to parse Sign of the Leviathan as more than a sketch, a working out of a musical idea, without a strong sense of direction or feeling of arrival. This may well be a consequence of the choice to work on material that is being considered ultimately for a different purpose. And it may also reflect Golijov’s evident decision not to employ the Hispanic, Jewish (both sacred styles and klezmer), and Arabic styles of his musics that have been prominent in some of his best-known work. Nevertheless, the performance was solid and impressive, both in the coloristic treatment of the string orchestra and in the extraordinarily challenging solo horn part.

The guest conductor on Monday was Ludovic Morlot, who chose two quite different works to open and close the concert. The first was the prelude to Wagner’s Parsifal; he ended with the complete Images for orchestra by Debussy. Morlot explained to me later that the choice of these two pieces was to provide different kinds of performing challenges to the players with works that they have most likely never performed before. The first was a piece of long-held notes unfolding sustained melody, in which continuity was most important, and the other score of spectacular color and variety made up of small motifs and figures creating a busy kind of discontinuity. Young orchestral players are far more likely to have experienced earlier Wagner and Debussy scores. Morlot commented, “The next time they play these, they will have a very different feeling how they work.” Both pieces were presented with masterly projection of their respective composers’ styles and full sonorous richness.

A special treat came in the performance of Paul Hindemith’s Konzertmusik for strings and brass, Opus 50, a work composed for the Boston Symphony’s 50^th anniversary in 1931, but all too rarely heard since then despite the fact that it is in the minds of many, including me, one of Hindemith’s finest works. The woodwinds enjoyed a vacation in this piece, while the strings and brass instruments, organized somewhat differently than in standard concert layout, are challenged from beginning to end. The two contrasting movements treat strings and brass both as sustained melodic instruments and as vigorous dynamic players, especially in the challenging fugue of the second movement.

Conductor Ruth Reinhardt did a splendid job of shaping these contrasting sounds so that the total ensemble could be clear, energetic, and exciting. Especially after hearing a performance as shapely and clear as this, one wonders why Hindemith’s score is not heard more often.

Steven Ledbetter is a free-lance writer and lecturer on music. He got his BA from Pomona College and PhD from NYU in Musicology. He taught at Dartmouth College in the 1970s, then became program annotator at the Boston Symphony Orchestra from 1979 to 1997.