The 2023 Robert Mann Chamber Series continues with the “wonderful, selfless music-making” (The Times, London) of the Brentano String Quartet, Ensemble-in-Residence at the Yale School of Music. The program opens with Mozart’s intriguing “Hoffmeister” String Quartet, a chamber gem of character and complexity. Two touching memorial pieces by James MacMillan follow: his brief and delicate Memento and the miniature For Sonny, rife with pizzicato nursery rhymes and harmonies of shifting tones, composed to honor the memory of a friend’s grandson. It is fitting that Brentano ends their performance with one of the last and most profound pieces by Beethoven, since the Quartet takes its name from arts patron Antonie Brentano, believed to have been Beethoven’s mysterious “Immortal Beloved.”