Book excerpt: Mozart's Piano Sonata No. 16 in C major, K 545 was written in 1788 and is sometimes known by the title, 'Sonata Facile' or 'Sonata Semplice'. Since its publication in 1805 - 14 years after the composer's death - it has become perhaps the most popular and best-loved of the Mozart piano sonatas.K 545 is in three movements - the well-known Allegro, an Andante and a lively Rondo Allegretto.The Sonata No. 1 in C major, K 279 was written in 1774 when the composer was just 18 years old, and is the first of the 18 Mozart piano sonatas. K 279 is in three movements - an Allegro, a lyrical Andante and a brilliant Allegro finale.