Through the widespread fame of his Miserere, Allegri’s name has become synonymous with the ethereal purity of polyphony (the art of combining two or more independent parts in harmonic accord). A composer and singer, he was born in Rome in 1582, joined the papal choir in 1629, and became director two years before his death in 1652. He composed exclusively for the church and was most at home in a conservative idiom built on the great achievements of the Renaissance, most notably Palestrina’s majestic fusion of expression and form. His best music is in the unaccompanied a cappella style, often for two interlocking choirs, and remained in the repertory of the papal choir for over a century. The “Miserere,” a nine-voice setting of Psalm 51 for Holy Week, was sung in the Sistine Chapel until the 1870s. The music is basically restrained, alternating verses in simple harmony and plainsong, but adorned with embellishments originally improvised by the singers. The famous high C, like much of the version generally heard today, was added after Allegri’s time.