Mozart’s String Quartet No. 21 in D Major, K. 575: Music for a Prussian King
In June of 1789, the 33-year-old Mozart began writing a set of six string quartets for Friedrich Wilhelm II, the King of Prussia, a passionate music lover and a fine amateur cellist. Mozart had played at the King’s Potsdam court during a tour the previous spring. Ultimately, Mozart was unable to fulfill the commission. After completing the first Quartet (K. 575), he became occupied with the opera, Così fan tutte. He returned to …