Composed in 1801, dedicated to Joseph von Sonnenfels.
Beethoven's Sonata No. 15 is at its most beautiful, a work of soulful and generous serenity that is nevertheless combined with great skill and subtlety.
The first movement is notable for its timpani-like bass buzz, first pretending to be in the dominant, G, murmuring like a heartbeat, and for the development, which increases fury by radically compressing the first theme of the sonata and presents 38 bars of immutable harmony that does not lead to recapitulation.
The second movement begins with a majestic and deep sadness, and only grows in complexity as it goes on, honestly, it is one of the most beautiful things that Beethoven has ever written.
The third movement is based on the contrast between long and short notes, and its trio is the same melody 8 times, although you wouldn't even notice it, so cunning and subtle it transforms each time.
The fourth movement is a gently rolling rondo, warmly whimsical in a naive way. It is also the first time that Beethoven has written ma non troppo in a work.