A challenge three hundred years in the making. Two of the most historically significant choirs of the 1500s, one based in Venice and one in Rome, will perform at St. Mark’s on March 24. The Venetian choir, today directed by Brazilian mons. Marcos Pavan, is the oldest extant choir, and their performance will include the famous Missa Papae Marcelli, composed by Giovanni Pierluigi da Palestrina to celebrate the election of Pope Marcellus II in 1555. Palestrina was born in Rome 500 years ago, while the other two composers in the programme are Venetians: Andrea and Giovanni Gabrieli. The programme will illustrate two opposing trends: while the Roman School focused on voice alone, the Venetian School allowed instrumental accompaniment, especially the organ. Amon the several ranks of workers in St. Mark’s Basilica, the title of First Organist was the most renowned appointment.