The Organ - a history

Instruments of this type date from antiquity. The organ evolved from the Middle Ages onwards and throughout the Renaissance, reaching a peak of perfection in the High Baroque period (1650 - 1700). Towards the end of the 16th century, organ design advanced to the stage where a large instrument consisted of several sections, virtually independent organs in themselves. First came the pedal section, connected to its own set of pipes, and later, the 'Rückpositiv', 'Oberwerk' and 'Brustpositiv' (see dictionary below). The end of the 19th century saw the introduction of electropneumatic systems which made playing easier.
The sound of an organ note is unvarying, and therefore largely excludes the possibility of dynamic expression. Even the development of 'swell' mechanisms in the beginning of the 18th. century (which introduced some dynamic variation) could not fundamentally alter the even tone of organ pipes. For this reason, the organ is best suited to polyphonic music with independent parts, as exemplified by the fugual composition of J.S. Bach and others.