The claviorgan (also known as the claviorganum,claviorgano, clavecin organisee) is a combination of a stringed instrument (usually a keyboard instrument) and an organ. Its origin is uncertain but its history can be traced back to the fifteenth century.
A number of "virgynalls with regals" are mentioned in the inventories of Henry VIII in 1542/3 and 1547 and Wilson Barry cites references to the claviorganum in England dating back to the 1530s. The term claviorgan in its strictest sense refers to the combination of a harpsichord (or other harpsichord type instrument) and an organ, although later could also be used to refer to a combination of a piano and organ. Michael Praetorius describes the claviorgan in his Syntagma Musicum of 1619 as
" ... a clavicymbal, or some other symphony, in which a number of pipes is combined with the strings. Externally it looks exactly like a clavicymbal or symphony, apart from the bellows, which are sometimes set at the rear and sometimes placed inside the body"
The spinet-regals are usually quite compact, especially compared to their larger harpsichord cousins. The spinet is often of the smaller Italian style in a square case, as opposed to the perhaps more familiar Bentside shape popular in Britain. The organ is usually a small regal, with the bellows perpendicular to the keyboard, and pipes with tiny resonators.
The instrument seems to have been very popular in Britain in the eighteenth century: both the larger harpsichord-organ combinations, and the organised-square pianos. Indeed there are more than 20 surviving examples built in the UK (mostly in London) of which the large portion date between 1700 and 1800.
The most complete British organised-harpsichord is that constructed for the Earl of Wemyss. The harpsichord is typical of the early and ornate work of Jacob Kirckman, with an organ case that matches the marquetry and elaborate figured veneer of the harpsichord. The harpsichord stop levers are laid out in the conventional fashion on either side of the name-board, with the organ stops being placed at either side of the keyboards with a coupling mechanism to the organ at the front of the harpsichord.