One of the greatest composers of all time. Bach wrote hundreds of pieces for organ, choir, as well as many other instruments. He spent most of his life as a church organist and a choir director. His music combines profound expression with clever musico-mathematical feats, like fugues and cannons in which the same melody is played against itself in various ways.
This very popular melody is believed to have been in fact composed by Gottfried Heinrich Stölzel (1690-1749). It appeared in Bachs Clavier-Büchlein für Anna Magdalena Bach (BWV 508).