The organ originated from Greece and the Greek word „organon“ as well as the Latin word „organum“, initially simply meant „tool“ or „instrument“. It was only in the late Roman times that the word organ started to define this particular musical instrument. During the migration period (barbarian invasions), the organ disappeared completely in the Occident, surviving only in the Eastern Roman Empire and the Arab world.
In the year 757, Emperor Charles the Great received an organ as a present from the Byzantine Emperor Constantine V. In order to copy this precious and unusual gift, priest George from Venice, known for his knowledge of antique organ building, was called upon. Thus the instrument was reintroduced into common use and development later to reach a peak in medieval times. The basic design of the Pipe Organ in it's essence, hasn't changed much since medieval times.
The smallest of the medieval organs was the Portative. Its name comes from the Latin verb portare to carry, and it is called that because it was small enough to be carried easily. The typical portative organ had:
The Portative Organ was so popular that images of Portatives can be found in many manuscript illustrations and Paintings of the twelfth through the fifteenth centuries.
Another Very common medieval Organ that did manage to survive in different forms into modern times is the Positive Organ. Modern Positive Organs usually have multiple ranks of pipes of different materials and timbres,, however the medieval Positive was very similar to the Portative with the exception of a larger range of notes and a dual bellow system for providing a continuous supply of wind.
While the Positive could be played by one person in much the same way as a portative,, it was most effectively played by two persons, one pumping the bellows and the other playing at the keyboard. Some very rare Portative Organs also adopted the dual bellow system to provide an uninterrupted wind supply,, however it should be noted that this difficults the ability to play expressive passages possible on portatives with a single bellow.