During the 1650s Cavalli was at the height both of his fame and his creative powers, and had reached his career's apex. This was the decade in which he published no less than fourteen of his thirty-two surviving operas and it was the decade in which he published the Musiche sacre (1656). The Musiche sacre of 1656 is a collection of music – of musical components, for satisfying the liturgical requirements of a wide range of feast days. Such portmanteau publications were fairly common during the seventeenth century but Cavalli's is a particularly comprehensive example of the genre. His setting of Laetatus sum, Psalm 121 (Psalm 122 in protestant bibles) would have been intended to be sung as the gradual proper on the fourth Sunday of Lent but could also be sung during second Vespers on many of the Feasts devoted to the Blessed Virgin and for both Vespers on most feasts of female saints. It's a lovely piece for alto, tenor, and bass voices with five instruments that's very operatic in conception and structure. As you listen you can hear the somewhat lenghty solo passage being passed from one soloist to another. Each soloist sings one verse over the bass line (it's the same bass line – Cavalli maintains it to provide continuity) giving us what is fact an operatic strophic aria of the type introduced by Monteverdi in his opera Orfeo. Cavalli added a further operatic touch by including a lively ritornello based upon the alto solo's opening notes. Enjoy :-).