Beethoven’s piano sonatas are among the most treasured compositions in the classical canon. He wrote 32 in all.
In 1801, Ludwig van Beethoven completed his 14th piano sonata, Op. 27 No. 2, and he gave it the descriptive title, “Sonata quasi una fantasia,” meaning roughly “Sonata like a fantasy.”
The sonata form traditionally follows specific rules that define how sections of the piece are composed and when they should occur. A fantasy is a free-formed style considered almost improvisatory. By this point in his composing, Beethoven was now taking more risks and stretching such formal definitions. His mixture of these two styles allowed the work more anticipation and surprise, perhaps leading to it becoming such a memorable and recognizable piece.
The first reference to the name, “Moonlight Sonata,” however, didn’t occur until 1832. Ludwig Rellstab coined the popularly known title saying it was reminiscent of the moonlight’s reflection off Lake Lucerne. Beethoven had died in 1827, five years prior.