RANCESCO DELLA ROVERS), pope from Aug. 9, 1471, to Aug. 12, 1484, was born of a poor family near Savona in 1414. He entered the Franciscan order at an early age and studied philosophy and theology at the universities of Padua and Bologna. He was chosen general of his order in 1464. Three years later he was, to his own surprise, made cardinal-priest of St. Pietro in Vincoli by Paul II., whom he succeeded as pope. Sixtus sent Cardinal Caraffa with a fleet against the Turks, but the expedition was unsuccessful. He continued to condemn the Pragmatic Sanction in France, and denounced especially the ordi nance of Louis XI. which required (Jan. 8, the royal p/acet for the publication of all papal decrees. He likewise continued his predecessor's negotiations with the Tsar Ivan III. for the reunion of the Russian Church with the Roman see and for sup port against the Turks, but without result. He was visited in 1474 by King Christian of Denmark and Norway, and in the following year (June 12) he established the University of Copen hagen. Sixtus soon abandoned his universal policy in order to concentrate attention on Italian politics, and showed himself a confirmed nepotist. He was cognizant of the conspiracy of the Pazzi, plotted (1478) by his nephew, Cardinal Riario, against Lorenzo de' Medici. He entered into a fruitless and inglorious war with Florence, which kept Italy for two years (1478-8o) in confusion. He next incited the Venetians to attack Ferrara, and then, after having been delivered by their general, Roberto Malatesta, from a Neapolitan invasion, he turned upon them and eventually assailed them for refusing to desist from the hostilities which he had himself instigated. He relied on the co-operation of Lodovico Sforza, who speedily forsook him; and vexation at having peace forced upon him by the princes and cities of Italy is said to have hastened his death (Aug. 12,
1484). Sixtus granted many privileges to the mendicant orders, especially to the Franciscans; he endeavoured to suppress abuses in the Spanish Inquisition; he took measures against the Wal denses; he approved the office of the Immaculate Con ception for Dec. 8; in 1478 he formally annulled the decrees of the council of Constance; and he canonized St. Bonaventura (April 14, 1482). The most praiseworthy side of his pontificate was his munificence as a founder or restorer of useful institutions, and a patron of letters and art. He established and richly en dowed the first foundling hospital, built and repaired numerous churches, constructed the Sistine chapel and the Sistine bridge, improved church music and instituted the famous Sistine choir, commissioned paintings on the largest scale, pensioned men of learning, and, above all, immortalized himself as the second founder of the Vatican library. These great works, however, were not accomplished without grievous taxation. Annates were increased and simony flourished.
See L. Pastor, History of the Popes, vol. iv., trans. by F. I. Antro bus (1898) ; M. Creighton, History of the Papacy, vol. iv. (i90i) ; F. Gregorovius, Rome in the Middle Ages, vol. vii., trans. by Mrs. G. W. Hamilton (1900-02) ; Jacob Burckhardt, Geschichte der Renais sance in ltalien (4th ed., ; J. A. Symonds, Renaissance in Italy; E. Frantz, Sixtus 'V. u. die Republik Florenz (Regensburg, 188o) ; I. Schlecht, "Sixtus IV. u. die deutschen Drucker in Rom," in S. Ehses, Festschrift zu elfhundertjdhrigen Jubildum des Campo Santo (Frei burg, 1897) ; Aus den Annaten-Registern der Piipste Eugen IV., Pius II., Paul II. u. Sixtus IV., ed. by K. Hayn (Cologne, 1896).