The earliest pianos by Cristofori (ca. 1700) were lightweight objects, hardly sturdier in framing than a contemporary harpsichord, with thin strings of low tensile strength steel and brass and small, tubular-shaped hammers. During the Classical era, when pianos first became used widely by important composers, the piano was only somewhat more robust than in Cristofori’s time.
It was during the period from about 1790 to 1870 that most of the important changes were made that created the modern piano. The prototype of the modern piano, with all of these changes in place, was exhibited to general acclaim by Steinway at the Paris exhibition of 1867; by about 1900, most leading piano manufacturers had incorporated most of these changes.