This grand piano, decorated with rosewood veneer and inlaid brass foliate bands, was probably purchased by George IV from Motts of Pall Mall. It originally stood in the Music Room Gallery at the Royal Pavilion (as can be seen in John Nash’s engraving of 1824). The inscription above the keyboard includes: Patent Sostenente Grand.

On 1 February 1817, Isaac Mott took out a patent for a grand piano incorporating improvements of his own invention, known as the Sostenente Grand Patent. This involved a way to sustain the sounds of the piano by means of a pedal-operated roller. As this instrument is dated 1817 it must be one of the first which Mott produced by virtue of his patent. However, the patented movement is no longer in the piano.