While Johannes Zumpe is considered to be the first maker and inventor of the English square piano (the earliest surviving examples are dated 1766) another maker, Harman Bernard Vietor, was probably making a form of square piano from about 1761. Vietor called his instrument a “Coelestin d’ Amour” or a “Forte ex Piano” and he claimed to be the inventor. Vietor’s business was at 19 Mercer Street, Longacre , Soho, London and in 1766 he moved to 32 Porter Street, Newport Market, St. Ann’s, Soho.
According to Rimbault, (The Pianoforte, its origin, progress and construction, 1860), Vietor was a German, already resident in London in 1760 and that he made several important improvements to the pianoforte prior to the arrival Americus Backers. (Americus Backers along with John Broadwood and Robert Stodart developed the English grand action.) An example of Vietor’s Forte ex Piano has survived and is dated 1767. It is a primitive instrument, and even more so than the early instruments by Zumpe. It uses a form of English single action. There are two sets of hammers and either set is engaged by a stop on the front of the case. One set of hammers has buff leather pads and the other set are wood only.
Vietor’s Forte ex Piano is not fitted with dampers and this suggests that the preference at that time was for a washy sound where the limited resonance of the vibrating strings continued for a short while. There is also a buff stop. The key levers are rack guided at the rear similar to the early square pianos by Zumpe.
Vietor also sold second-hand musical instruments from his shop in Porter Street. An advertisement that appeared in the Daily Advertiser on 16th May 1768 read: “To the admirers of music. To be disposed of the following curious musical instruments. Two fine toned upright harpsichords of four stops in mahogany cases, one of new rectangular construction with four front doors, the other in the form of a bookcase with a writing desk and six drawers underneath very nicely made with ornaments. A very strong sound double bass with wheel machines of four strings, made in Italy. Two well-tuned David’s or German harps with seven pedals. Two violins, one of Jacobus Stainer and one Cremonien with a tenor of Stainer. To be seen at Mr. Vietor’s in Porter Street, St. Anns Soho”.
In 1769 Vietor advertised a large fortepiano with pedal for “shift and movement” in a mahogany harpsichord case. This could be an early English grand piano and therefore it would pre-date the earliest extant example by Americus Backers of 1772. Vietor was also an organist at the Lutheran church, and a teacher of the harpsichord. The instruments by Vietor failed to find favour with the public in contrast to those by Zumpe and by 1772 Vietor had vacated the premises at 32 Porter Street.