Organ Sonata in C minor

At a glance

• What it isthe third and final movement of Organ Trio Sonata No. 2. The theme enters in turn, as in a fugue.
• Who, when, whyone of the six pieces Bach gathered in Leipzig around 1730.
• What to listen forthe moments when the same theme appears in the right hand, the left hand and the feet in turn.

Listen for

• First entryone hand brings out the theme alone. When the other hand enters with the same theme, the first lays a new line on top.
• The theme in the feetafter the hands have traded the theme, listen for whether the feet tread it on the pedals. In the low register the same theme sounds different.
• The closeafter passing through several keys, the theme returns to C minor and the movement ends firmly.

When it was written

The fugue was a technique Bach refined all his life: a single theme taken up by several voices in turn and woven together. He wrote a great many fugues for organ and keyboard, and in his last years he devoted himself to a collection called The Art of Fugue.

This set of trio sonatas survives in Bach's own fair copy. After his death the manuscript passed through his sons and pupils, and once it was printed in the nineteenth century it became important study and concert music for organists.