Although Bach had dreamt of establishing a ‘well-regulated church music’ since his early days, it was only between 1723 and 1750 that he finally had the chance to do so, as Kantor and Director Musices in Leipzig. Here he invented the ‘modern’ cantata, combining chorales and traditional biblical texts with arias and recitatives on freely composed texts. The four cantatas recorded by Philippe Herreweghe offer a magisterial demonstration of the transition from cantatas initially judged ‘too theatrical’ to a perfectly achieved form – as in the cantata BWV 84, among the very last to be written.