Benedetto Marcello (1686-1739) was an Italian composer, writer, and theorist. His early studies were on the violin, which he soon abandoned in favor or singing and writing counterpoint. A merciless critic, he lampooned the operas of Vivaldi and his contemporaries in his satirical Il teatro alla moda (Venice, c. 1720). Among his pupils were the singer Faustina Bordogni and the composer Baldassare Galuppi. Marcello composed a number of operas and stage works, as well as vocal and instrumental music. Marcello is best remembered for his vocal music of all kinds--sacred and secular, small scale and large scale. It was the setting of the first fifty psalms (with Italian paraphrase by G. A Giustiniani) in cantata form that won him particular acclaim. Eight volumes of Estro poetico~armonico were produced in Venice between 1724 and 1726. 'Coeli enarrant etc.' ('The Heavens Are Telling') is the first section (verse 1) of Psalm XVIII. In the modern Bible, 'The heavens are telling' is Psalm XIX:1. 'Psalm XVIII' is in the key of C, and is scored for alto, two tenors, bass and continuo. There are a total of nine sections that vary in length and texture, including solos, solo quartet, tutti chorus, and chordal and fugal styles. Tempi range from presto to largo, and the text is developed or through-composed. A section may consist of a single verse or several verses. As in other psalms of Estro poetico armonico, Marcello includes a section based on Hebrew chant (vs. 8-12, which alternate between solo and chorus as well as an ecclesiastical intonation (v. 16b). 'Psalm XVIII' is unusual, however, in that Marcello also uses Greek chant (v. 15).