This pianos is one of the earliest William Rolfe pianos. According to Martha Novak Clinkscale (vol.2) the firm Rolfe & Davis was established in 1785 and William Rolfe alone made pianos under his name from about 1789. With his colleague Samuel Davis he filled a patent in 1797 for a stop which gives the effect of Turkish drums and cymbals!! 

According to Clinkscale This is the earliest record of Janissary music on fortepianos but I found once another 18th century second hand piano advertisement in Russia (!!) which addressed Turkish music noises on that piano for sale! 

Most probably reading the paragraph above is a big surprise but that is true and is a part of the history.