Born on 11 November 1542 in San Martino dall'Argine[1] (or in Mantua according to other sources[2]), he belonged to the family of the Dukes of Sabbioneta, his father Carlo being the Marquess of Gazzuolo.

[3] Throughout his life he patronized literature and men of letters, among the latter being Tasso, who sought his advice concerning his Gerusalemme Liberata, and Guarini, who dedicated to him his Il pastor fido.

Having finished his theological studies he went to Rome, became cameriere segreto to Pope Pius IV, and was ordained priest on 1 November 1579.

[4] On 18 December 1587, at the request of the Duke of Mantua, raised him to the cardinalate with the title of cardinal priest of Santa Maria del Popolo.

[1] The three books of his Commentarii, an autobiography written in polished Latin, are an important source of information for the history of his cardinalate; they were edited at Rome in 1791.