The relationship between piano manufacturer and composer is interactive, and consequently both compositions and performance styles evolved organically due to this relationship. Early on, the instrument had more influence on the composer, whereas with the instrument’s establishment, composers began to exert more influence on the subsequent development of the instrument through their requests of manufacturers. The relationship between pianist-composers and manufacturers is important for pianists to study and understand, as well as the actual sound of a composer’s fortepiano and the way he performed on it. Through studying the development of the piano and the relationship between manufacturers and composers, pianists can reinterpret compositions before the mid nineteenth century, such as Mozart, Beethoven, Dussek, Chopin, and Liszt, using their knowledge of the aforementioned to bring a different perspective to their performances on the modern piano. There are numerous manufacturers and composers who made important contributions to the development of the piano. This dissertation focuses on selected pianist-composers and fortepiano manufacturers, and the impact of their relationship on piano literature before 1860.