Agazzari, Agostino, Italian organist, music theorist, and composer; b. Siena, Dec. 2, 1578; d. there, April 10(?), 1640. He went to Rome, where he was maestro di cappella at the Collegio Germanico (1602–03) and the Seminario Romano (1606–07). About 1606 he was made a member of the Accademia degli Intronati in Siena, where he was given the name Armonico Intronato. He then returned to Siena, where he was organist at the Cathedral and later may have served as its maestro di cappella. Agazzari was the author of the influential treatise Del sonare sopra 7 basso con tutti li stromenti e dell’uso loro nel conserto (Siena, 1607), one of the earliest works on thoroughbass. He also publ. La musica ecclesiastica dove si contiene la vera diffinitione della musica come scienza, non più veduta, e sua nobiltà (Siena, 1638), an endeavor to bring the practice of church music into accord with the Resolution of the Council of Trent. He composed a dramma pastorale, Eumelio (Rome, 1606). He also publ. 17 vols, of sacred vocal works (1602–40), including masses, Psalms, litanies, and motets, which are notable for their continuo accompaniment, and 5 vols, of madrigals (1596–1607).
I C. Reardon, A. A. and Music at Siena Cathedral, 1597–1641 (Oxford, 1994).
—Nicolas Slonimsky/Laura Kuhn/Dennis McIntire