Thanks to making a lot of money from composing and performing, Johannes Brahms decided to take early retirement at age 55. He kept that promise for five years until he turned 60 and met Richard Mühlfeld, the principal clarinettist of the Meiningen Orchestra. That chance meeting produced the crown jewels of the clarinet repertory: a quintet, a trio and two sonatas.
There is an autumnal feeling to this piece. Its late Brahms, looking into an open grave and saying, I had a good run, but that looks like a tombstone with my name on it. This is a four handkerchief piece. That opening melisma on the two violins sets the tone.
After the long development section comes the recap. The coda is a cry from the heart, ending with complete sadness on a low B from the clarinet.
This video repeats the exposition, which is a blessing because its so beautiful.