Split keys on historical organs between 1468 and 1721 by Ibo Ortgiesby Ibo Ortgies | Het ORGEL | Year 96 | (2000) | Issue 6
Het ORGEL 96 (2000), nr. 6, 20-26 [summary]
Split keys offered a rather convenient way to exceed the limitations of restrictedtemperaments and tunings in keyboard instruments, since the essential features of thesetemperaments were kept, like for example the pure major thirds of meantone temperament.
It seems to have been Italian organ builders of the mid-15th-C. who were the first toapply split keys in organ building. Italy was the main center of this development for thefirst 150 years. Shortly after 1600 however, Germany, which was dominated by musiciansunder Italian influence, took the central position.
Split keys were promoted by the Wolfenbüttel Hofkapellmeister MichaelPraetorius and the Saxon court organ builder Gottfried Fritzsche. From this geographicalarea the idea spread to surrounding regions and countries. With the rise of circulatingtemperaments the practice disappeared soon after 1700.
About 70 Instruments with 13-16 keys per octave are known to have been built in Italy,Spain (?), Germany, the Netherlands, England, Sweden and Denmark.