The choice of presenting composers from what might be called music's suburbs - perhaps "shtetls" better conveys their true position of isolation and oppression - was the  bold inspiration last weekend of music director Mario Venzago, whose charge is normally to give guided tours of music's great metropolitan centers, with their host of marquee players and well-tooled traditions.

            Leading the ISO in one of Sibelius' most extensive pieces representing his Finnish identity - the Lemminkainen Suite - was perhaps only slightly eccentric. Taking seriously the hero of the Kalevala, the Finnish national epic, made for an even edgier decision. Lemminkainen, whether his exploits as warrior and lover are to be seen  as events in a heroic quest or (as Venzago suggested in remarks from the stage) the mere stirrings of his mind and heart - is a strenuously rakish, exhausting hero.

            For Sibelius to enter so convincingly the raw emotional terrain of the character is startling enough, yet  the composer's artistic impersonation was firmly seconded by the tense, mysterious performance the conductor drew from the ISO. Of course, despite this work's uncanny qualities, for many years Sibelius has been at home in the mainstream concert world, despite a considerable backlash against his lionization in the middle decades of the 20th century.

            Much  bolder, given the marginalization of the native peoples of North America from the dawn of white settlement to the present, was Venzago's decision to program two works by contemporary American Indian composers: "Incident at Wounded Knee" by Louis Ballard, and the  late Quapaw/Cherokee composer's "Indiana Concerto" for Piano and Orchestra, completed by the Mohican Brent Michael Davids.

            A complex orchestral palette immediately presents itself in "Procession," the opening movement of "Incident at Wounded Knee," and its anguish carries over, appropriately solemnified,  into the second-movement "Prayer."  These parts of the programmatic work seemed most individualistic, with the concluding pair of movements, "Blood and War" and "Ritual,"  occupying the more conventional territory of bringing an ethnic musical heritage safely within the precincts of the Western symphonic tradition.

            Ballard's distinctive regard for his heritage emerges immediately in the first movement of the piano concerto, its solo part convincingly taken by the Italian pianist Emanuele Arciuli. The bare, pentatonic melodic lines, unsoftened by much harmonic coloring, give a clearcut salute to the music of his people, somewhat replicating the stripped-down sophistication of Chavez's and Revueltas' appropriation of native Mexican music.

            Davids' more discursive structures and diverse orchestration marked the final two movements, starting with a remarkable "hero's journey" at least as interior as Lemminkainen's  -- and certainly less hectoring, while just as impressive in its own way, as Siegfried's Rhine Journey. Titled "Music Box Manitou," the movement sets the piano and the orchestra on parallel courses - the latter representing the rich background of a people as absorbed through history and personal memory, the former placing - first tentatively, then with more confidence - a Davids/Ballard persona in delicate relationship to it. Risks were taken with material so undramatically laid out, but the movement held the attention marvelously well.

            The finale, "Stomp Dance for Louis,"  had aspects of American Indian dances as presented for white audiences, something for tourists to lap up superficially and record on camera. But it delved deeper into apparently authentic overlaid rhythmic patterns and made good use of  the solo instrument as an independent source of color and figurative profiling. It continued to look within, in other words, just as the two movements preceding it had done in different ways.  But this time, there was a note of assertiveness and even triumph in the music to set poised against forces that, unwittingly or not,  continue to dissipate the heritage that nurtured Ballard and that Davids extends devotedly on his behalf.