The Missa Solemnis is the work Beethoven regarded as the summation of his art - not the Ninth Symphony, not the late quartets. For all the inherent conventionality of its format, it stands outside its period and at one remove from any tradition. It is a gigantic, sprawling testimony modern enough to challenge audiences and performers today.

Written in 1823, it is also a relatively modern score for Paul McCreesh and his Gabrieli Consort. One might have expected them to whip through at brisk period-instrument pace, but the performance, lasting around 80 minutes, was thoughtful and even measured. The Kyrie began almost tentatively, its overlapping vocal lines a prayer that gradually grew in assurance with repetition. Indeed, the only really irresistible surge of energy in the whole work came with the opening of the Gloria, trumpets and strings galvanised into action by the timpani.

Rather than smoothing out the work's corners or cushioning its abrupt mood swings, McCreesh's interpretation played to its strangeness. The result was not always absolutely convincing; the last section of the Credo seemed tacked on, an unnecessary embellishment to the rest of the movement.

Yet there was a stark, solemn beauty to the performance, thanks partly to the rawness of the period instruments. McCreesh resisted the temptation to make the Benedictus too comforting; Catherine Martin's violin solo was bang in tune but, played almost completely without vibrato, a little detached.

The choir, however, was mellifluous when McCreesh asked, especially the tenors in Et Incarnatus Est; and there was a sumptuous quartet of soloists in Susan Gritton, Christianne Stotijn, Werner Güra and Neal Davies. The Agnus Dei offers an unsettling lack of consolation, its prayer for peace undermined by echoes of martial drums; in this, Davies's eloquent bass solo could almost have been the voice of Beethoven himself.