PIUS IV. (Giovanni Angelo Medici, or "Medighino"), pope from 1559 to 1565, was born at Milan on March 31, 1499. He began his career as a lawyer, but later entered the service of Piul III., who made him a cardinal in 1549. In the protracted conclave that followed the death of Paul IV. the election of Pius (Dec. 25, 1559) was due to a compromise between the Spanish and French. In temperament Pius was affable, vivacious, con vivial. He was, moreover, astute, diplomatic and experienced in affairs. He allowed the reform movement initiated by Paul IV. free course, but tried to repair certain injustices of Paul IV., and mitigated some of his extreme decrees. But to the nephews of Paul he showed no mercy : they were charged with various crimes, condemned, upon testimony of suspicious validity, and executed on March 5, 1561. With England lost to the papacy, Germany overwhelmingly Protestant, and France on the verge of civil war, Pius realized how fatuous was the anti-Spanish policy of his predecessor. He therefore recognized Ferdinand as emperor, and conciliated Philip II. with extensive ecclesiastical privileges. But subsequently, antagonized by Philip's arrogance, he assisted France with troops and money for use against the Huguenots.
After a suspension of ten years the council of Trent reconvened on Jan. 18, 1562. Among the demands presented by the various nations were the recognition of the equality of the episcopate, communion in both kinds, clerical marriage and the use of the vernacular in Church services. It required all the pope's diplo
macy to avoid compliance on the one hand, and a breach with the powers on the other. Thanks to Morone and Borromeo, how ever, he achieved his end. The council was dissolved on Dec. 4, 1563, and its decrees and definitions confirmed by the pope (Jan. 26, 1564), who reserved to himself the sole right of interpretation, and took various measures for enforcing its decisions.
After the termination of the council Pius indulged his desire for ease and pleasure, to the great offence of the rigorists. Pius fortified Rome, and contributed much to the embellishment of the city—among other works, the church of Sta. Maria degli Angeli in the Baths of Diocletian; the Porta. Pia; the Villa Pia in the Vatican Gardens; and the Palace of the Conservatori. He died on Dec. 9, 1565, and was succeeded by Pius V.
See Panvinio, continuator of Platina, De vitis pontiff. rom. (a contemporary of Pius) ; Ciaconius, Vitae et res gestae summorum pontiff. rom. (Rome, 16oi-o2 ; also contemporary) ; T. Milner, Das Konklave Pius IV. (Gotha, 1889 ; more comprehensive than the title suggests) ; Ranke, Popes (Eng. trans., Austin), i. 323 seq., 358 seq.; and v. Reumont, Gesch. der Stadt Rom. iii. 2, 534 seq., 73o seq.