J.S. Bachs Magnificat was first performed in the Thomaskirche in Leipzig. In Rome, in time-honored tradition, the Pope invited the College of Cardinals and other guests from the worlds of politics and high society to a Christmas celebration at which a newly- commissioned work was performed for their edification. The music was composed by the teenager Giovannino del Violoncello, alias Giovanni Battista Costanzi. Filippo Leers, a well-known member of the Accademia dell Arcadia, wrote the libretto.