Giulio Cesare Monteverdi (1573–1630/31) was an Italian composer and organist; he was the younger brother of Claudio Monteverdi.Giulio Cesare Monteverdi was born in Cremona where he was baptised on 31 January 1573. In 1600 he held the position of organist of Mantua Cathedral for a brief time. In August 1602 he served as a musician at the court of the Duke of Mantua. On 2 June 1608, during the wedding celebrations at the Mantuan court, he composed the music for the fourth intermedio (words by Chiabrera; music lost), as part of a performance of Guarini's play L'Idropica. In 1609 Francesco Gonzaga (governor of Montferrat at the time) appointed him maestro di cappella. In this position, he wrote his opera Il rapimento di Proserpina (libretto by Ercole Marigliani), on the occasion of the birthday of Francesco's wife. A performance was given at Casale Monferrato in 1611 (music lost).In 1612 he was dismissed, along with his brother and other artists, from the Gonzaga court. Later on he became organist of the principal church at Castelleone, near Crema. Yet again he was appointed maestro di cappella at the Salò cathedral (10 April 1620). He died around 1630/31 in Salò, Lake Garda, possibly a victim to the plague.Only a small amount of his music survives, which includes a collection of 25 motets under the title Affetti musici, ne quali si contengono motetti a 1–4 et 6 voci, per concertarli nel basso per l'organo (Venice, 1620). The influence of his brother is evident to some extent, as can be seen in a madrigal for three voices and continuo, along with two other pieces, found in his brother's three-part Scherzi musicali (1607). Stylistically they resemble the rest of the volume's pieces, each with a three-part ritornello; the writing for the voices suggests a concertato manner notwithstanding the melodious character. Nevertheless, his most notable contribution is his editing of the volume, as well as including a Dichiaratione, where Claudio's ideas are discussed in detail. This Dichiaratione is found in the preface to Claudio's fifth book of madrigals, written in response to Artusi's attacks on him.