madrigal. Transition from the concertato madrigal In the first decade of the 17th century, the Italian compositional techniques for the madrigal progressed from the old ideal of an a cappella vocal composition for balanced voices, to a vocal composition for one or more voices with instrumental accompaniment. The inner voices became secondary to the soprano and the bass line; functional tonality developed, and treated dissonance freely for composers to emphasise the dramatic contrast among vocal groups and instruments. The 17th-century madrigal emerged from two trends of musical composition: (i) the solo madrigal with basso continuo; and (ii) the madrigal for two or more voices with basso continuo. In England, composers continued to write ensemble madrigals in the older, 16th-century style. In 1600, the harmonic and dramatic changes in the composition of the madrigal expanded to include instrumental accompaniment, because the madrigal originally was composed for group performance by talented, amateur artists, without a passive audience; thus instruments filled the missing parts. The composer usually did not specify the instrumentation; in The Fifth Book of Madrigals and in the Sixth Book of Madrigals, Claudio Monteverdi indicated that the basso seguente, the instrumental bass part, was optional in the ensemble madrigal. The usual instruments for playing the bass line and filling inner voice parts, were the lute, the theorbo (chitarrone), and the harpsichord. The madrigalist Giulio Caccini (1551–1618) produced madrigals in the solo continuo style, compositions technically related to monody and descended from the experimental music of the Florentine Camerata (1573–1587). In the collection of solo madrigals, Le nuove musiche (The New Music, 1601), Caccini said that the point of the composition was anti-contrapuntal, because the lyrics and words of the song were primary, and balanced-voice polyphony interfered with hearing the lyrics of the song. After Caccini's developments, the composers Marco da Gagliano (1582–1643), Sigismondo d'India (1582–1629), and Claudio Saracini (1586–1630) also published collections of madrigals in the solo continuo style. Whereas Caccini's music mostly was diatonic, later composers, especially d'India, composed solo continuo madrigals using an experimental idiom of chromaticism. In the Seventh Book of Madrigals (1619), Monteverdi published his only madrigal in the solo continuo style, which uses one singing voice, and three groups of instruments — a great technical advance from Caccini's simple voice-and-basso-continuo compositions from the 1600 period. Beginning around 1620, the aria supplanted the monodic-style madrigal. In 1618, the last, published book of solo madrigals contained no