"No other composer of the 19th century had such a close and informed relationship to music of the past," writes John Eliot Gardiner of Brahms. It is that relationship between Brahms and his musical forebears that is explored in Gardiner's latest project with his Monteverdi Choir and Orchestre Révolutionnaire et Romantique: five programmes spread across two seasons that will place some of Brahms's greatest achievements, the German Requiem and the four symphonies, in the context of the 18th- and early 19th-century music that shaped them.

The first two concerts showed how revealing the approach can be. Gardiner prefaced the Requiem with works by Schütz, Ahle and Bach's Cantata No 60, O Ewigkeit, du Donnerwort, which the Monteverdi Choir sang in Brahms's orchestration, with its extra vocal and instrumental doublings. There was also a striking Brahms rarity, his Begräbnisgesang Op 13, for mixed chorus, wind and timpani, whose stark austerity prefigures the sound world of the second movement of the Requiem itself. In the latter, the ORR's gut strings, with vibrato strictly rationed, and its wind and timpani raw-edged, conjured some tellingly powerful sonorities. Gardiner reserved the moments of greatest grandeur for the massive fugues in the second and sixth movements, while accompanying the soloists, soprano Katherine Fuge and baritone Dietrich Henschel, with a careful, intimate clarity.

Though the focus of the second concert was the First Symphony, limned in bold, dynamic shapes by Gardiner, there was more vocal music to preface it: Brahms's arrangements of a couple of Schubert's choral songs, and the Alto Rhapsody, sung with compelling intensity by Natalie Stutzmann. But in both the symphony and the Haydn Variations, which had begun the concert, the uncertain, often ill-tuned playing - the woodwind had a particularly unhappy evening - took some of the bloom off the performance.