Pietro Andrea Ziani italian composer and organist. He was organist at SSalvatore, Venice, and was active as an opera composer from 1654. He was maestro di cappella at S Maria Maggiore, Bergamo, 1657-9; in 1662 he became vice-Kapellmeister to the Dowager Empress Eleonora in Vienna, where like Cesti he was a leading champion of opera. In 1669-77 he served as first organist of St Mark's, Venice, succeeding Cavalli. He then became honorary court organist in Naples, and in 1680 maestro di cappella . Ziani's c 20 operas reflect the trend towards the use of purely musical forms and have strong comic elements. He also wrote several oratorios (notable for their counterpoint), sacred and secular vocal music and sonatas.