There were four big convents in Venice, and when Vivaldi got the music job in the Pio Ospedale della Pieta in 1703, he embarked on a career in which life, love, and art were to become inextricably entwined. The teenage nuns in this convent were either orphans or the abandoned daughters of war widows and prostitutes.
They were an acknowledged sex market, but at the same time they represented a large pool of high-grade musical talent. One French traveller observed:
"There is nothing so diverting as the sight of a young and pretty nun in a white habit, with a bunch of pomegranate blossoms over her ear, conducting the orchestra and beating time with all the grace and precision imaginable."
And by a young contralto called Anna Giro and her sister, Vivaldi was very diverted. Giro sang in many of his operas, and her absences from Venice coincided exactly with his when he went on tour.
The playwright Carlo Goldoni, who came to stay in the apartment where the composer and the two young women lived, left a vivid description of Anna:
"She was not pretty but she had charms - a delicate figure, beautiful eyes, beautiful hair, and charming mouth, and not much of a voice but much acting ability."
Not much of a voice? Listen to what counter-tenor Andreas Scholl extracts from the graceful "Salve Regina" (Vivaldi: Nisi Dominus, Decca 466 964-2), which must be one of the works the composer wrote for her.