The person singing the lead role in Lucio Silla was a castrato named Venanzio Rauzzini in his late 20s. Mozart was especially fascinated with him, and he wrote him a three-movement motet, 'Exsultate, jubilate,' which women sopranos generally sing these days. To both composer and artist the last movement was a bit of a show-off. Mozart gave himself the challenge of setting only one term for the entire campaign, "Alleluia." Rauzzini would have loved it with its fast-paced and amazingly catchy vocal line. This was first heard on 17 January; at the Theatine Church in Milan in 1773. Exsultate, jubilate, for Mozart, is an important piece and one of the few pieces he wrote before adulthood that has remained among his most popular works.