I learned at school that Claude Montal was the one who invented the sostenuto, but according to Wikipedia: ----------- The sostenuto was first shown at the Paris Exhibition of 1844, by Boisselot and Sons, a Marseille company. French piano builders Alexandre Francois Debain and Claude Montal built sostenuto mechanisms in 1860, and 1862, respectively. These innovative efforts did not immediately catch on with other piano builders. In 1874, Albert Steinway perfected and patented the sostenuto pedal. ----------- As far as I know, the sostenuto pedal was not so common in European (and Japanese) pianos even in 1970's.
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