"Joseph Freiherr von Sonnenfels (1732 – 25 April 1817) was an Austrian and German jurist and novelist. He was among the leaders of the Illuminati movement in Austria, and a close friend and patron of Mozart. He is also the dedicatee of Ludwig van Beethoven´s Piano Sonata No. 15, Op. 28, which was published in 1801." - (en.wikipedia.org 31.01.2020)
