Around the turn of the 18th century, the chalumeau was modified by converting one of its keys into a register key to produce the first clarinet. This development is usually attributed to German instrument maker Johann Christoph Denner, though some have suggested his son Jacob Denner was the inventor. This instrument played well in the middle register with a loud, shrill sound, so it was given the name clarinetto meaning "little trumpet". Early clarinets did not play well in the lower register, so players continued to play the chalumeaux for low notes. As clarinets improved, the chalumeau fell into disuse, and these notes became known as the chalumeau register. Original Denner clarinets had two keys, and could play a chromatic scale, but various makers added more keys to get improved tuning, easier fingerings, and a slightly larger range. The classical clarinet of Mozart's day typically had eight finger holes and five keys.