Another chain of development in the early harpsichord was a gradually increasing size. The psaltery was a hand-held instrument, far smaller than the fully evolved harpsichord. Early harpsichords were evidently small in both pitch range and string length. This can be seen, for instance, in the work of Sebastian Virdung, his "Musica getutscht" (Basel 1511). Virdung describes three instruments he calls the "Virginal", the "Clavicimbalum", and the upright "Claviciterium". These had pitch ranges of 38, 40, and 38 keys, respectively, far smaller than later instruments. Frank Hubbard believed that all three must have been "ottavini", meaning instruments that sound an octave above normal pitch. Since pitch range is linked to string length, an ottavino is one way of building a small instrument. Ottavini were also common later on in the early history of the harpsichord.