[1] Of versatile genius, Antonio was initiated to the ecclesiastical career, under the protection of one of the most authoritative Florentine prelates of the early sixteenth century, Cardinal Niccolò Ridolfi.
In 1548, as a poke in the eye to Cosimo, Pope Paul III appointed Bindo's son, Antonio Altoviti, as Archbishop of Florence.
Furious by this open affront, Cosimo I. retaliated by banning the new archbishop from setting foot in the city and even seized all the income and assets of the diocese.
He entered the Florence with so much pomp, solemnity and court of nobles, that Cosimo I. was so irritated, understanding this triumphal event as a humiliation of his sovereign authority, but ordinated in the same year his nephew Alessandro Ottaviano de' Medici, to whom Antonio Altoviti a mentor, succeeded him as archbishop and became Pope Leo XI.
He was a man of virtue with admirable pastoral supervision, which he also wanted to emphasize in his coat of arms depicting a dog guarding a flock, with the motto non dormit qui vigilat.