225. Pius IV:
December 25, 1559 - December 9, 1565 (5 years)
One of the most important actions taken by Pope Pius IV was to reconvene the Council of Trent on January 18, 1562, which had been suspended ten years earlier.
226. St. Pius V:
January 1, 1566 - May 1, 1572 (6 years)
A member of the Dominican order, Pius V worked hard to improve the position of the papacy. Internally, he cut expenditures and externally, he increased the power and effectiveness of the Inquistion and expanded the use of the Index of Forbidden Books.
227. Gregory XIII:
May 14, 1572 - April 10, 1585 (12 years, 10 months)
Gregory XIII (1502-1585) served as pope from 1572 through 1585. He played an important role at Council of Trent (1545, 1559-63) and was a vociferous critic of German Protestants.
228. Sixtus V:
April 24, 1585 - August 27, 1590 (5 years)
While still a preist, Perettie was a fiery opponent of the Protestant Reformation and his work was directly supported by powerful figures in the Church, including Cardinal Carafa (later Pope Paul IV), Cardinal Ghislieri (later Pope Pius V), and St. Ignatius of Loyola.
229. Urban VII:
September 15, 1590 - September 27, 1590 (12 days)
Urban VII has the unfortunate distinction of being one of being one of the shortest-lived popes ever - he died just 12 days after his election (apparently of malaria) and before he could even be coronated.
230. Gregory XIV:
December 5, 1590 - October 16, 1591 (11 months)
Gregory XIV had a relatively short and unsuccessful pontificate. Weak and invalid even from the start, he would eventually die due to a large gallstone - reportedly 70 grams.
231. Innocent IX:
October 29, 1591 - December 30, 1591 (2 months)
Pope Innocent IX reigned only a very short period of time and, during that time, he doesn't seem to have had a chance to do very much.
232. Clement VIII:
January 30, 1592 - March 5, 1605 (13 years)
The most important political event during Clement VIII's papacy was his reconciliation with Henry IV of France when Clement recognized the latter as King of France in 1595 - despite the Edict of Nantes
