Imaginatively programmed around two masterpieces of string-quartet writing, this Castalian String Quartet album is a triumph. Lassus’ haunting, late-16th-century setting of a poem about the return of light after darkness sets the very special tone and ushers in Beethoven’s late String Quartet No. 15 in A Minor, which explores mortality while seeking to step outside time. The Castalians play it with moving humanity and empathy for its anguish and hope. Thomas Adès’ The Four Quarters (2011) follows the time of a day, but it too seems to escape time in “The Twenty-fifth Hour.” The album closes centuries earlier with Dowland’s plea for sleep—or perhaps death.