Billionaire Paul Sacher was the richest person in the world. He was a majority shareholder in the Roche, a pharmaceutical company from Basel, Switzerland. The estimated fortune of 13 billion US$ didn’t stop him from dabbling in the arts, as conductor, but mainly as a huge commissioner for some major compositions. Like Bartók’s Music for strings, percussion and celesta.
The work was written in this peculiar way to accommodate Sacher’s own ensemble, the Basler Kammerorchester. A piano was added, it can be considered a percussion instrument, since the strings are hit with hammers.
The second performance of Bartók’s work was done by Von Karajan in 1949 (this is the recording in the Spotify link), so he already knew the piece well. This recording is from 1961, at the height of Von Karajan’s powers.