He was born in 1600 in Borgo San Sepolcro, son of a nobleman, Giovanni Battista Aggiunti. He first studied literature at the College of the Nobles of Perugia under the guidance of Bonciario. Then he attended the College of the Sapienza in Pisa, where, in addition to gaining a deep knowledge of Latin and Greek, studied Aristotelian and Platonic philosophy, jurisprudence under Francesco Accarisi, and geometry and astronomy under Benedetto Castelli. After six years of study he earned a Doctorate in 1621 in philosophy and law, and immediately afterwards was appointed by the reigning Grand Duchesses of Tuscany as companion of literary studies to the young Grand Duke Ferdinando II, with the rank and stipend of a man of letters in his service. It was probably in this period that he became a close disciple of Galileo. So it happened that, having entered on familiar terms with the Grand Duke, when in 1626 the chair in mathematics at the University of Pisa became vacant, he was called to occupy it, with Galileo’s high recommendation. His lessons were extremely popular, and among those who attended them were the Dukes of Lorena and Guisa, and on several occasions both Princes of Tuscany. He was likewise Prince Giovanni Carlo’s instructor in mathematics, and in 1634 served as Prince Mattias’ all-round tutor. He also wished, with Galileo’s help, to transfer from his post at Pisa to the chair at Padua, and perhaps also to the one at Bologna, mainly to help his dear friend Dino Peri, thus leaving him the post at Pisa; but the plan never went through. He died in the flower of his years, on his very birthday, December 5, 1635, in Pisa.

The Works of Galileo Galilei, national edition edited by Antonio Favaro, Florence, Barbèra, 1899-1909, vol. XX, Biographical Index, to v.