 Such instruments are often generically called fortepianos.In the 1960s, Lubin frequented the New Hampshire workshop of Philip Belt, a pioneering American builder of fortepiano replicas, and became curious how Mozart's piano concertos would have sounded on these instruments in their original performances.In the mid 70's, he built a fortepiano replica of his own, with the help of a piano technician friend, Lee Morton, who had served as Belt's apprentice.