The Toronto Mendelssohn Choir crowned its season on Tuesday night at Koerner Hall with a powerful, majestic, thrilling performance of one of the most sublime works in the entire choral repertoire: Johann Sebastian Bach’s Mass in B Minor, BWV232.

The B Minor Mass is an extraordinary one-off among the great choral works for several reasons. First, its sheer scale renders it virtually unusable for the church liturgy as the music lasts for a good solid two hours, give or take a bit. Second, it is unlikely that it was ever performed in Bach’s lifetime, since he finished it only in the last year of his life, 1749 (although there were performances under his direction of the majestic Sanctus and one or two other portions). Indeed, the earliest documented performance of the complete work finally took place over a century after his passing, in 1859. Third, this score makes great demands on the skills of singers and instrumentalists alike, demands which make it one of the most challenging works in the repertoire.

Bach created the B Minor Mass by bringing together numerous works which he had written earlier in his life, and then substantially recomposing many of them for this new purpose. In line with several of his other great works from his last years, it seems quite possible that he composed and assembled the Mass as a kind of textbook or anthology of the many stylistic possibilities for accompanied voices in the late Baroque era. With such a checkered ancestry, it’s remarkable that the Mass has such remarkable unity-in-diversity, the music flowing forward with clear purpose and momentum through each of the liturgy’s five main sections.

The key designation of “B minor” refers (as with Bach’s short masses) only to the key in which the music begins — that is, the key of the opening Kyrie eleison. From the first notes of the Gloria onward, with the appearance of the natural trumpets in D, the key of D major becomes the centre of gravity around which the remainder of the work revolves.

For this performance, the Toronto Mendelssohn Choir’s Music Director, Jean-Sébastien Vallée chose to feature ten voices from within the Choir’s professional core, the Toronto Mendelssohn Singers, as soloists in the various solo and duo numbers.

While all ten did fine work, special praise is due to counter-tenor Simon Honeyman who sang three of the five numbers allotted to the alto/mezzo-soprano with crystal-clear articulation in the rapid passagework and a real sense of feeling above all in the penultimate Agnus Dei. Also particularly remarkable was the unanimity of style between Honeyman and soprano Sinéad White in their joyful Christe eleison. Due for special praise was Rebecca Claborn’s beautifully shaped and phrased Laudamus te.

Above all, the Mass in B Minor stands or falls by the work of the chorus. Scholars have substantially concluded that Bach meant the music to be sung with one voice to a part, and many experts sneer at the idea of a chorus of one hundred as we heard on this occasion.

The Choir’s splendid clarity in the interwoven polyphonic lines could well give those scholars pause. The very opening Kyrie eleison displayed absolute clarity of texture, permitting the hearer to follow any one line out of the polyphonic texture with no difficulty.

The Choir went on from strength to strength throughout the performance, from the lively, enthusiastic In gloria Dei patris to the formally shaped Gregorian chant lines of the Credo in unum Deum, and from the mysterious depths of the Qui tollis and Et incarnatus est to the joyful exuberance, even exhilaration, of the Et resurrexit and Osanna.

More than any other moments, the Choir reached the heights of their performance in the grave majesty of the Sanctus and the Dona nobis pacem.

With a decent-sized but not overlarge orchestra playing on authentic instruments, the audience was able to hear Bach’s instrumental lines much as the composer would have heard them, particularly true of the D trumpets, the natural horn in the Quoniam, and the duet of two wooden transverse flutes. Matthew Larkin’s playing on the chamber organ, the sole keyboard continuo instrument, created a secure underpinning for the entire performance.

Music Director Jean-Sébastien Vallée shaped the performance with care, avoiding interpretive excesses and stressing above all the unity of style from movement to movement. In that opening Kyrie, he had directed the Choir to a specially clear articulation of the lines, and his sparing use of that device throughout the evening always heightened the audibility of the parts without spilling over the edge. He also avoided excessively loud fortes and soft pianos in perfect keeping with Baroque-appropriate style.

With all of these careful touches and many more, Vallée brought the entire world of the B Minor Mass to vivid life. The ecstasies, the meditations, the sorrows, the joys, and the overwhelming majesty were all there, and rightly so.

The capacity audience in Koerner Hall were moved to sustained cheering at the concluding standing ovation. And no wonder — this was, in every way, the finest B Minor Mass I have ever heard in a live performance.