The Greek engineer Ctesibius of Alexandria is credited with inventing the organ in the third century BC. Portable organs were invented in the Middle Ages. Towards the middle of the thirteenth century, the portatives appear to have real keyboards with balanced keys. Large organs such as the one installed in 1361 in Halberstadt, Germany by Guillaume de Machaut (...) Until the mid-fifteenth century, most large organs had no stop controls. Each manual controlled many ranks at multiple pitches. This large number of ranks was called the Blockwerk.
New organs featured well-balanced mechanical key actions, giving the organist precise control over the pipe speech. Schnitger's organs featured particularly distinctive reed timbres and large Pedal and Rückpositiv divisions.
The organ became more symphonic, capable of creating a gradual crescendo, more variation in sound and timbre, and more divisions.Organs began to be built in concert halls (such as the organ at the Palais du Trocadéro in Paris)
The development of pneumatic, electro-pneumatic, and electric key actions in the late nineteenth century made.
Electronic organs developed throughout the twentieth century. Many pipe organs were replaced by
digital organs because of their lower purchase price, smaller physical size, and minimal maintenance requirements.
(Repairing, manufacturing, spare parts, prices and quotations, technical questions)