father of the astronomer Galileo and a leader of the Florentine Camerata, a group of musical and literary amateurs who sought to revive the monodic (single melody) singing style of ancient Greece.

Galilei studied with the famous Venetian organist, theorist, and composer Gioseffo Zarlino (Zarlino, Gioseffo) (1517–90) and became a noted lutist and composer. Several books of his madrigals and instrumental music were published in his lifetime, and he is said to have been the first to write solo songs (now lost) in imitation of Greek music as it was then understood.

Galilei engaged in heated attacks on his former teacher Zarlino, particularly on his system of tuning, and published several diatribes against him. Among these is the Dialogo della musica antica, et della moderna (1581; “Dialogue about Ancient and Modern Music”), which contains examples of Greek hymns (among the few known fragments of ancient Greek music). In the same work he attacked the practice of composition in which four or five voices sing different melodic lines simultaneously with different rhythms, thus obscuring the text and ignoring the natural rhythm of the words; this practice was typical of the Italian madrigal style that Galilei came to despise and that went out of fashion in the 17th century.