There are two types of pedal piano: the pedal board may be an integral part of the instrument, using the same strings and mechanism as the manual keyboard, or, less frequently, it may consist of two independent pianos (each with its separate mechanics and strings) which are placed one above the other, a regular piano played by the hands and a bass-register piano played by the feet.
The origins of the pedal piano are found in the pedal clavichord and pedal harpsichord, of which an original of the former survives and the latter only survives in descriptions and modern reproductions. The first citation of a clavichord with pedalboard appeared around 1460 in a section dedicated to musical instruments in an encyclopedic treatise written by the scholar Paulus Paulirinus (1413-1471). Organists would use these instruments for practise when they had no-one available to work the bellows for a church organ or, in the wintertime, to avoid having to practice on a church organ in an unheated church. Johann Sebastian Bach owned a pedal harpsichord and his organ trio sonatas BWV 525-530, Passacaglia and Fugue in C minor BWV 582, and other works sound well when played on the instrument.
Wolfgang Amadeus Mozart owned a fortepiano with independent pedals, built for him in 1785 by Anton Walter. He mentions improvising in public on such an instrument in letters to his father. In the autographed manuscript of the Concerto in D minor K 466, composed the same year, the bass notes is evident.
Louis Schone made a pedalflügel for Robert Schumann in 1843, when he was in Dresden. Schumann preferred an upright pedal piano; his pedal keyboard had 29 notes and was connected with an action placed at the back of the piano where a special soundboard, covered with 29 strings, was built into the case. Schumann wrote much music for the pedal piano and was so enthusiastic about the instrument that he convinced Felix Mendelssohn, who owned a grand pedal piano, to form a class devoted to it in the Leipzig Conservatory. Charles-Valentin Alkan owned a Pleyel pedal piano and composed a number of works for it, in the virtuoso style to be found in his other piano music. Kevin Bowyer has revived some of this music in recent years, though he plays it on the organ.
The instrument never became very popular in the 1900s, and it remains a rarity. It is mostly used to enable organists to practice at home, rather like the pedal harpsichord and clavichord were centuries ago, instead of being used to play the pedal piano repertoire. In the 2000s, pedal pianos are made in the Borgato workshop in Italy. This company makes an independent bass-register instrument connected to a pedal board, on which a concert grand can be placed. Borgato expanded the register of the bass piano to 37 notes (rather than the standard 30 or 32 on an organ).