 That music from 1864 by Johannes Brahms, the second of his string sextets, G major, Op. 36, with members of the Academy of St. Martin-in-the-Fields Chamber Ensemble. That written really in memory of a woman to whom he was engaged, and he makes musical reference to her name, Agatha, in some of the motifs in that piece. A little more by Brahms. This is the Stenschen Serenade, sung by Christa Ludwig.