Fugue

A contrapuntal composition following a strict tonal plan. It is a texture rather than a form. It opens with a theme in one part in the tonic which is then repeated by each part alternating in the dominant and the tonic. It may have as few as two voices and rarely more than four. The difference from imitation is that in imitation the theme may be repeated by another part at any degree of the scale. The fugue became an important texture or compositional device in later Baroque and reached its height in the works of JS Bach.

Typical of seventeenth century German keyboard music. Pieces with alternating free (prelude) and fugal sections. The closing section nearly always reverts to the free writing of the opening.