If Johann Sebastian Bach is the fountain from which Western music springs, then Leipzig is its source. The German city is a place of musical pilgrimage: not only can you pay homage at the Thomaskirche, where Bach was Thomaskantor for 27 years until his death in 1750, but you can visit the first marital home of Robert and Clara Schumann, and the last known residence of Felix Mendelssohn, who was the Gewandhaus Orchestra’s Kapellmeister for the last 12 years of his life.

But for nine days every summer, Leipzig is Bach’s city. The annual Bachfest Leipzig is a thriving festival brimming with new ways of interpreting the composer, different performance philosophies and never-ending combinations of his own with other composers’ music. Three concerts over one day at the opening weekend provided a chance to tip one’s toe into Bach’s enormous legacy.

Bach was the starting point for the MDR Symphony Orchestra’s matinee programme at the city’s Gewandhaus. Arman Tigranyan’s orchestration of the Partita no. 2 in D minor for solo violin showed that there are always new ways to hear his music This rousing and majestic arrangement, full of brass pomp and robust string writing, spoke to the structural and harmonic grandeur implicit in Bach’s solo works.

Although overshadowed by their more prestigious neighbours, the MDR Orchestra are a plucky and impressive ensemble, energised by the tireless direction of chief conductor Kristjan Järvi. In Rachmaninov’s Second Symphony – a world away from Bach, granted – they found their groove after a slightly ragged entry, and danced along with verve to Järvi, who was busting a whole repertoire of moves that wouldn’t have been out of place on Strictly Come Dancing.

It is hard to imagine what the north German church organist with a prodigious work ethic would have made of Sibelius, a melancholy Finn with a weakness for liquor and a taste for the good life. To celebrate 100 years of Finnish independence, Bachfest invited the young Finnish chamber choir Dominante to join Leipzig’s own city chamber choir for a performance in the Thomaskirche itself that put the two composers’ choral music side by side.

Sibelius’ settings of Finnish and Swedish texts are melancholic and wistful. Rakastava, a setting of traditional Finnish folk poems, is a short song cycle imbued with both the magic and sorrow of nature; the image of a singing bird, imitated by the choir, turns sour when it flies away like the protagonist’s sweetheart. These poems were positively pagan in comparison to the funereal devotion of Bach’s Komm, Jesu, Komm, which had an eerie magic of its own, performed just yards away from Bach’s final resting place.

The influence of Martin Luther looms larger over Bach’s music than perhaps any of his musical predecessors. Not only did Bach spend much of his lifetime composing music for protestant services at Leipzig, but also used several of Luther’s own chorale melodies as the basis of his works, including the cantatas written for services on Sundays and feast days of the liturgical year. These mini oratorios draw out the week’s gospel message in intense musical dramas, and form one of Bach’s greatest legacies to choral music.

To mark 500 years since the reformation, the Bachfest presented multiple performances of Bach’s Leipzig cantatas, intended to be a complete cantata cycle for the 1724-25 liturgical year, but never completed. As well as interpretations by heavyweights including John Eliot Gardiner, Masaaki Suzuki and Ton Koopman, John Butt and the Dunedin Consort gave stirring interpretations of three cantatas from the cycle, as well as the Easter oratorio Christ lag in Todes banden, at the city’s Nikolaikirche.

The ensemble’s impassioned strings, mellifluous wind and buoyant continuo (led by John Butt from the harpsichord) was matched by declamatory singing from the choir and quartet of soloists, of whom warm-toned alto Emilie Renard was the stand-out in this difficult acoustic. Whilst Bach can speak to music from Rachmaninov to Sibelius in new and fascinating ways, there is nothing quite like the unrivalled bliss of Bach spoken directly, without frills and with total conviction.