The first books of madrigals that Gesualdo published are close in style to the work of other contemporary madrigalists. Experiments with harmonic progression, cross-relation and violent rhythmic contrast increase in the later books, with Books Five and Six containing the most famous and extreme examples (for instance, the madrigals "Moro, lasso, al mio duolo" and "Beltà, poi che t'assenti", both of which are in Book Six, published in 1611). There is evidence that Gesualdo had these works in score form, in order to better display his contrapuntal inventions to other musicians, and also that Gesualdo intended his works to be sung by equal voices, as opposed to the "concerted madrigal" style popular in the period, which involved doubling and replacing voices with instruments. In addition to the works which he published, he left a large quantity of music in manuscript. This contains some of his richest experiments in chromaticism, as well as compositions in such contemporary avant-garde forms as monody. Some of these were products of the years he spent in Ferrara, and some were specifically written for the virtuoso singers there, the three women of the "concerto di donne".