The second sextet must be the first European work that I read about that premiered in America. Boston, 1866 to be exact. Brahms wrote two sextets, scored for two violins, two violas and two cellos in a timespan of five years. This second one contains a reference to a personal memory.
In 1858 Brahms was staying with the family Grimm in Göttingen, where he met the sweet Agathe von Siebold. She had a good voice and a lovely nature, and Brahms wrote songs for the first and started an intimate friendship for the second. After two years the parents demanded he either married her, or put a stop to the affair. 24 year old Brahms was not ready for marriage, so the two broke up. A sore memory for both, so Brahms dedicated his second sextet to her by using her name as the basis for one of the melodies: a-g-a-d-h-e (h = b in German notes).
Listening to this recording made me very happy. It is subtle and very beautifully played. A pity Spotify doesn’t have it. I am trying not to do YouTube links, because they have a tendency to disappear over time, but do try to find it and listen to it.