Giulio Romolo Caccini (also Giulio Romano) (8 October 1551 – buried 10 December 1618), was an Italian composer, teacher, singer, instrumentalist and writer of the very late Renaissance and early Baroque eras. He was one of the founders of the genre of opera, and one of the most influential creators of the new Baroque style. He was also the father of the composer Francesca Caccini.
Little is known about his early life, but he was born in Italy, the son of the carpenter Michelangelo Caccini; he was the older brother of the Florentine sculptor Giovanni Caccini. In Rome he studied the lute, the viol and the harp, and began to acquire a reputation as a singer. In the 1560s, Francesco de' Medici, Grand Duke of Florence, was so impressed with his talent that he took the young Caccini to Florence for further study.
By 1579, Caccini was singing at the Medici court. He was a tenor, and he was able to accompany himself on the viol or the archlute; he sang at various entertainments, including weddings and affairs of state, and took part in the sumptuous intermedi of the time, the elaborate musical, dramatic, visual spectacles which were one of the precursors of opera. Also during this time he took part in the movement of humanists, writers, musicians and scholars of the ancient world who formed the Florentine Camerata, the group which gathered at the home of Count Giovanni de' Bardi, and which was dedicated to recovering the supposed lost glory of ancient Greek dramatic music. With Caccini's abilities as a singer, instrumentalist, and composer added to the mix of intellects and talents, the Camerata developed the concept of monody—an emotionally affective solo vocal line, accompanied by relatively simple chordal harmony on one or more instruments—which was a revolutionary departure from the polyphonic practice of the late Renaissance.