[2] His mother was the sister of Pope Julius III and niece of Cardinal Antonio Maria Ciocchi del Monte.

He joined the Knights Hospitaller at an early age, taking the religious name "Giulio" in honor of his family's benefactor, Pope Julius II.

[3] He entered the court of his uncle, Cardinal Giovanni Maria Ciocchi del Monte, the future Pope Julius III.

[7][3] It was Fulvio della Corgna who was responsible for the founding of the seminary in Perugia and for inviting the Jesuits to the city to establish a college, the first Rector of which was Everard de Mercœur (Mercurian).

[3] In 1553, Cosimo de' Medici, Duke of Florence, fearing that the fighting in Tuscany might expand into a larger war between the Empire (Charles V) and France (Henri II), which would be severely damaging to his territories, urgently requested the Pope to send negotiators to work out an understanding.

On 2 August the French, who had invaded Tuscany under Marshal Blaise de Montluc, were defeated at the Battle of Marciano, and forced to retreat into Siena, where they fomented a coup-d-état in their own interests.

But the fact that Vercelli had recently fallen to Marshal de Brissac and the Duke of Savoy had been killed (16 August) gave the French, enjoying one success after another, the courage to decline to settle.

[17] On 30 January 1566 he opted for the titular church of San Lorenzo in Lucina, and then, on 3 March 1567, for Sant'Adriano al Foro, another deaconry assigned as titulus.

[3] As the most senior cardinal-priest residing in the Roman Curia, he opted for the order of cardinal bishops on 5 May 1574, taking the suburbicarian Diocese of Albano.