Drawing of a harp made by Sébastien Érard.
harp made by Sébastien Érard
before 1911 <div style="display: none;">date QS:P,+1911-00-00T00:00:00Z/7,P1326,+1911-00-00T00:00:00Z/9</div>
Encyclopædia Britannica, 11th ed., Vol. 13, p. 14.