Ludwig van Beethoven left us 35 piano sonatas actually. The three sonatas from his days in Bonn, published in 1783, do not have an opus number and therefore do not appear in the canon of 32 sonatas. However, these demanding early works are not to be underestimated. Their piano technique is challenging, particularly because of their differentiated articulation while their compositional technique points far ahead into his Viennese days. The main theme of the Second Sonata in F minor (1st movement) already presages the main theme of the 1st movement of the Grande Sonate pathétique.