(Gioseffe), Italian music theorist and composer; b. Chioggia, probably Jan. 31, 1517; d. Venice, Feb. 4, 1590. Zarlino received academic training from the Franciscan monks, his teacher in music being Francesco Maria Delfico. In 1537 he took minor orders and in 1539 was made a deacon. He was active as a singer during 1536 and organist in 1539-40 at Chioggia Cathedral. After his ordination he was elected capellano and mansionario of the Scuola di S. Francesco in Chioggia in 1540.

In 1541 Zarlino went to Venice to continue his musical training with Adrian Willaert. In 1565 he succeeded his fellow pupil Cipriano de Rore as maestro di cappella at San Marco, holding this position until his death. He also was chaplain of S. Severo from 1565 and a canon of the Chioggia Cathedral chapter from 1583. His students included G. M. Artusi, Girolamo Diruta, Vincenzo Galilei, and Claudio Merulo.

Zarlino's historical significance rests on his theoretical works, particularly Le istitutioni harmoniche in 1558. In this work, he describes the MAJOR and MINOR THIRDS as INVERSIONS within a FIFTH, and consequently, as mutual mirror reflections of component INTERVALS, anticipating the modern theories of Jean-Philippe Rameau, Giuseppe Tartini, Moritz Hauptmann, and Hugo Riemann. He also gives lucid and practical demonstrations of DOUBLE COUNTERPOINT and CANON, illustrated by numerous musical examples. While adhering to the system of 12 MODES, he places the IONIAN rather than the DORIAN mode at the head of the list, thus pointing toward the emergence of the major SCALE as the preponderant mode. He also gives 10 rules for proper syllabification of the text in musical settings.

Zarlino's theories were attacked, with a violence uncommon even for the polemical spirit of the age, by Vincenzo Galilei, his former pupil, in two pamphlets from the 1580s. In reply to the first of Galilei's books, Zarlino published Sopplimenti musicali in 1588. In the latter, he suggests EQUAL TEMPERAMENT for the tuning of the LUTE.

As a composer, Zarlino was an accomplished craftsman. He wrote both sacred and secular works.