copyist's mistake. Sources Two complete copies of Agresta's Madrigali a sei voci ... Libro primo survive, one in the Collection 'G. Thibault' of the Bibliothèque nationale de France in Paris, the other in the library of the Conservatorio di Musica San Pietro a Majella in Naples; both are in good condition, and each is identical to the other. The print is on the large part free from errors. The contents of Madrigali a sei voci ... Libro primo Keith Larson has dealt extensively with the contents of Agresta's Madrigali a sei voci ... Libro primo; here are some extra details to his analysis. Numbers 1 to 8 are written in an 'ordinary' clef combination (Canto and Sesto in C1 clef, Alto in C3 clef, Tenore and Quinto in C4, and Basso in F4), while numbers 9 to 15 are written in 'high' clefs (Canto and Sesto in G2, Alto in C2, Tenore and Quinto in C3, and Basso in F3 – commonly known as chiavette), suggesting downwards transposition. If one follows Adriano Banchieri's suggestion in his 1614 Cartella musicale of transposing pieces written in chiavette down by a perfect 4th when the printed key signature contains one flat and by a perfect 5th when it contains no flats, the transposed ranges of the individual voice parts of numbers 9 to 15 all become rather lower than the ranges of numbers 1 to 8. Depending on the singers involved in a performance, a downwards transposition of either a tone or a minor 3rd for numbers 9 to 15 is suggested. The last piece in the collection, 'Io penso e nel pensar' is unusual in many ways. The anonymous poem is a dense play on the words 'penso' ('I think'), 'pensar' ('to think') and 'pensier' ('thought'); most striking is its use of frequently changing time signatures, which are different in each part, including such proportions as 1:10, 14:6, 6:5 and 3:7. Larson describes it as 'an intellectual challenge to virtuoso singers', while Watkins suggests that its 'novel and highly mannered proportional complexities ... while appearing theoretical as well as anachronistic, may well be an attempt by the composer to suggest expressive tempo variability'. The texts The choice of poetry comprises both old and new authors, and the majority of the texts are also set by many other composers. These include four by Giambattista Marino, four by Petrarch and two by Giovanni Battista