The architect Giacomo Barozzi da Vignola had been taken up by the papal family of the Farnese and worked with Michelangelo, who had deeply influenced his style.

Vignola has from 1564 carried on Michangelo's work at St. Peter's Basilica, and is to construct the two subordinate domes according to Michelangelo's plans.

He begins work on the church of Sant'Anna dei Palafrenieri in 1565: his oval-based plan, like his earlier design for the church of Sant’Andrea in Via Flaminia, represents a radical break with the Renaissance classical tradition.

Pope Pius IV, a lavish patron of scholars and artists, including the late Michelangelo, dies on December 9, 1565, having restored good relations between the papacy and the Habsburg dynasty under the guidance of his nephew Carlo Borromeo, archbishop of Milan.

Carlo Borromeo, whose family had intended him from childhood for a career in the church, had held many important offices in Rome while his late uncle, Giovanni Angelo de'Medici, reigned as Pope Pius IV.

Upon the death of his uncle, Borromeo takes part in the conclave that on January 7, 1566, elects Dominican Cardinal Ghislieri, a member of the Roman Inquisition.

Born into a poor family at Bosco Marengo, Antonio (also called Michele) Ghislieri, had held a series of important offices in the Dominican order.

Attracting the favor of Pope Paul IV for the austerity of his life and his zeal for orthodoxy, he had in 1557 been made a cardinal.

Ghislieri is crowned Pope Pius V on January 17, his sixty-second birthday.

Borromeo takes up residence in Milan in April of 1566 as archbishop and cardinal, gaining renown as a reformer who champions the ideals of the recently adjourned Council of Trent.

He has served in executing its decrees and is largely instrumental in bringing out the Roman catechism, decreed by the Council.

A champion of the Counter-Reformation, Borromeo actively sponsors the conversion of Swiss Protestants.

He pays particular attention to convocation and visitation of his clergy, to promoting the instruction of the laity in Christian doctrine, and to reorganizing the administration of his archdiocese.

Borromeo, beset in Milan by political and other turmoils, has become embroiled with the Milanese Senate and with Governor Luis de Requesséns y Zúñiga as well as with the rebellious canons of Santa Maria della Scala and the order of the Humiliati (The Humble Ones).

Borromeo nevertheless has the support of many religious congregations, including his own Oblates of St. Ambrose.

One of the Humiliati, the priest Girolamo Donato Farina, attempts in 1569, to assassinate Borromeo; despite the archbishop's pleas for leniency, Farina and his accomplices are tortured and executed.

Archbishop Carlo Borromeo continues to reside at Milan, where serious administrative problems confront him.

He has regularly visited his more than one thousand widely scattered parishes, which fall under the jurisdictions of King Philip II of Spain and also of Venice, Genoa, and Novara.

His heroic behavior during the plague of 1576–78 has won him much respect.

Borromeo has fostered clerical education by establishing seminaries and colleges at Milan and in the Italian cities of Inverigo and Celano.

Colleges for lay students also have been erected and entrusted to the Jesuits.

The archbishop's last undertaking is the opening of the college at Ascona, Switzerland, in 1584; he dies at home on November 3.