Even though Fortunato Chelleri was a composer of many forms, the substance of his eighteenth century stature arose from his composition of instrumental music, which he wrote in the later years of his career (approximately 1729 and onward); these include symphonies, duos, trios, partitas, solos, and numerous sonatas and fugues. Prior to the time in which he composed instrumental music, he primarily wrote operas and oratorios. As a child, he was in the chapel choir of the Madonna della Steccata and was educated in voice and keyboard by his uncle and guardian Frencesco Maria Bazzani (maestro di cappella of the Piacenza cathedral). Shortly thereafter, in Spain and Italy, Chelleri created nearly a dozen operas, beginning with Zenobia in Palmira (1709), then La caccia in Etolia (1715), Ircano innamorato (1715), Alessandro fra le Amazoni (1715), Penelope la casta (1717), Alessandro Severo (1719), Temistocle (1720), and L'innocenza difesa (1721). Although most of the music of these dramas has been lost, records indicate that many of his works of this type were performed and/or premiered in established theaters of Venice, Padua, and/or Florence.
After departing from Spain around 1710, Chelleri was made maestro della cappella di camera by elector Palatine Johann Wilhelm and then by Karl III Philipp. While it is uncertain as to whether or not he was employed by Anna Maria Lusia de' Medici, he did unquestionably serve Philipp Franz von Schonborn in Würzburg as Hofkapellmeister and then as Court Councillor in 1723. It was there that he wrote the majority of his oratorios, which include Per la morte del Rendentore (1722 - 1724), Maria virgine (1722 - 1724), De annuntiatione B. Mariae V. (1723), and Allegorie (1724). Before leaving this post for the position of Kapellmeister to the Landgrave Karl of Hesse-Kassel, which later transformed into a post of Hofrat under Wilhelm, Chelleri wed Apollonia Theresia Papius. He had three sons and stayed in Kassel for the remainder of his life, except during an extended trip to England and during brief employment for Friedrich in Stockholm. In his lifetime, Chelleri also wrote several cantatas, including Amor, più non m'inganni (1727), Pupille e fin a quando, Quanto mai sarai più bello, and Su le deserte sponde. ~ Meredith Gailey, Rovi