Before Ghislieri could return to his episcopate, Pius IV. died, and on January 7, 1566, he was elected to the papal chair with duly attendant prodigies, his coronation taking place on his birthday, ten days later. Fully alive to the necessity of restoring discipline and morality at Rome to ensure success without, he at once proceeded to reduce the cost of the papal court, compel residence, regulate inns, expel prostitutes, and assert the importance of ceremonial. In his wider policy, which was characterized throughout by a stringency which tended to defeat its own ends, the maintenance and increase of the efficacy of the Inquisition and the enforcement of the canons and decrees of the Tridentine council had precedence over all other considerations. The prudence of Comniendone alone saved him at the commencement of his pontificate from trouble with Germany, as in the general diet of the empire at Augsburg (March 26, 1566) Pius saw a threatened invasion of his own supremacy and was desirous of limiting its discussions. In France, where his influence was stronger, he directed the dismissal of Cardinal Odet de Coligny and seven bishops, nullified the royal edict tolerating the extra-mural services of the Reformers, introduced the Roman catechism, restored papal discipline, and strenuously opposed all compromise with the heretics - his exertions leading up in no small degree to the massacre of St Bartholomew.
In the list of more important bulls issued by him the famous bull "In Coena Domini" (1568) takes a leading place; but amongst others throwing light on his character and policy there may be mentioned his prohibition of quaestuary (February 1567 and January 1570); the condemnation of Michael Baius, the heretical professor of Louvain (1567); the reform of the breviary (July 1568); the denunciation of the dirum nefas (August 1568); the banishment of the Jews from the ecclesiastical dominions except Rome and Ancona (1569); the injunction of the use of the reformed missal (July 1570); the confirmation of the privileges of the Society of Crusaders for the protection of the Inquisition (October 1570); the prohibition of discussions concerning the miraculous conception (November 1570); the suppression of the Fratres Humiliati for alleged profligacy (February 1571); the approbation of the new office of the Blessed Virgin (March 1571); the enforcement of the daily recitation of the canonical hours (September 1571); and the purchase of assistance against the Turks by offers of plenary pardon (March 1572). His antagonism to Elizabeth I was shown, not only in the countenance lent by him to Mary Stuart and those who sought in her name to deliver England "ex turpissima muliebris libidinis servitute", but in the publication of a bull, dated April 27, 1570, excommunicating Elizabeth and releasing her subjects from their allegiance.
His energy was in no respect more favourably exhibited than in his persistent and successful endeavours to form a general league against the Turks, as the result of which the [battle of Lepanto]? (Oct. 7, 1571) was won by the combined fleet under Colonna. Three national synods were held during his pontificate - at Naples under Cardinal Alfonso Caraffa (whose family had, after inquiry, been reinstated by Pius V.), at Milan under Carlo Borromeo, and at Machim. His death took place on May 1, 1572, and he was canonized by Clement XI. on May 24th 1712. He was succeeded by Gregory XIII.
from the 9th edition (1888) of an unnamed encyclopedia.