An album by Italian mezzo-soprano Cecilia Bartoli is invariably an occasion, always imaginatively programmed and immaculately performed. Were it not for the lockdowns of 2020, however, this collection of virtuoso concert arias might never have seen the light of day. With unexpected time on her hands, Bartoli turned to her recorded archive in search of unreleased material. Recorded back in 2013 with the Basel Chamber Orchestra and, on two of the tracks, the great violinist Maxim Vengerov, Unreleased features seven dramatic concert arias by Beethoven, Mozart, Mysliveček, and Haydn, each written as vocal showcases. The Mozart and Beethoven works were inspired by a specific singer: one the 18th century’s finest sopranos, Josepha Duschek. Bartoli dispatches the technical challenges here with consummate ease, style, and engaging musicianship.