‘Ecco mormorar l'onde’, deservedly the best-known madrigal of Monteverdi's Second Book (1590), occupies a centrally important place within that volume; it represents a particularly rich version of imitatio (see Chapter 3, above), and established durable new models for musical form and tonal organisation. Anna Maria Monterosso Vacchelli has suggested that it is also the central madrigal of an interrelated group of three, ‘Mentr'io mirava fiso’, ‘Ecco mormorar l'onde’ and ‘Dolcemente dormiva la mia Clori’ (Nos. 12, 13 and 14 in the Second Book), together projecting the most modern aspect of the volume. (These are their numbers in the first edition, not in the less reliable later editions, nor in Malipiero's Collected Edition.)

Essential models for modern style in the Second Book include Marenzio, already identified in Chapter 3, above, and the Eighth Book of Madrigals for five voices (1586) of Giaches de Wert, a friend of Tasso, who supplied most of Monteverdi's texts for this volume. ‘Ecco mormorar l'onde’ interweaves two sharply different models from Wert's Eighth Book, ‘Io non son peròmorto’ and ‘Vezzosi augelli’; both have been identified hitherto, but only in isolation from one another.