SIXTUS IV, Pope. - Born at Celle near Savona in 1414 to Leonardo della Rovere and Luchina Monleone, of very modest condition. He became a Friar Minor quite young, studied at Pavia and Bologna and completed his courses at Padua, where he obtained his doctorate in theology on 14 April 1444 and then taught philosophy and theology with great acclaim (cf. G. Brotto - G. Zonta, La Facoltà teologica dell'Università di Padova, Padua 1922, p. 170 ff.). He then taught at Bologna, Pavia, Siena, Florence and Perugia. He was then procurator of the Order at Rome, vicar of the general for all Italy, provincial of Liguria, and in 1463 he took part in the dispute on the Blood of Christ before Pius II. In 1464 at Perugia he was elected general of the Order, and in 1467 at Florence he presided over the General Chapter. On 18 Sept. 1467 Paul II created him cardinal of St. Peter in Chains. On the death of Paul II, after a conclave lasting barely three days, Cardinal della Rovere was created pontiff on 9 Aug. 1471 with the name Sixtus IV and crowned on the 25th.
Lavish and free in spending, Sixtus left the papal finances at his death completely drained; but he particularly showed his liberality toward his relatives, who hastened to fill the court, dragging along numerous fellow countrymen; ecclesiastical and civil offices and benefices were lavishly distributed to them. Leonardo was the son of Bartolomeo, the Pope's brother, the "prefettino" of Rome who soon vanished; the other brother Raffaello had a far more numerous offspring: Giuliano, who was later Julius II, Giovanni, who became lord of Sinigallia and then prefect of Rome, Luchinetta, married first into the Gara, then into the Franciotti, Bartolomeo, a Friar Minor, later bishop of Massa and invested with high offices. The Pope also had two sisters: Bianca, married into the Riario (v.), and Luchina, married into the Basso, from whom came Girolamo Antonio, cardinal. In the brief time he lived, it was Cardinal Pietro Riario (d. 5 Jan. 1474) who "held both keys" to the Pope's heart, while Cardinal Giuliano della Rovere, because of his frequent absences, did not exercise a preponderant influence. He who did dominate, so much so that he could be called Ecclesiae imperator, was Girolamo, brother of Cardinal Pietro, for whom the latter had in 1473 obtained the lordship of Imola and the hand of Caterina Sforza.
Sixtus IV's first purpose was that of war against the Turk, who was growing ever more threatening; he thought at first of gathering a council for this purpose; then he sent five cardinal legates to the princes of the West (23 Dec. 1471); then together with Naples and Venice he armed a fleet that operated in the East under Cardinal Oliviero Carafa and then under Archbishop Lorenzo Zane (1472-73).
Paul II's policy had been to keep Italy at peace by overcoming the ambitions and jealousies of the princes and at the same time to keep the City tranquil from its ever-reviving internal discords. Sixtus IV at first, in the face of the Milan-Venice-Florence union, allied himself with Naples and Siena (1476), whence came the Pazzi conspiracy against Lorenzo de' Medici favored by Girolamo Riario (26 April 1478), the excommunication of Lorenzo and the interdict against Florence, the war waged by Naples and the Pope; until, peace having been made between Naples and Florence (March 1480), the Pope too acceded to it. In the meantime Sixtus IV had formed an alliance with Venice; however, he again had to provide against the Turkish danger and to aid the Knights Hospitaller in their victorious resistance at Rhodes, and to intervene at the side of the king of Naples when in July 1480 the Turks seized Otranto, from which they were not driven back until 10 Sept. 1481. Peace was again disturbed in Italy when in May 1482 war broke out between Venice and Ferrara; soon Naples too moved against Venice; the Colonna sided with Naples and had the Orsini against them; the Neapolitan army moved against Rome but on 21 Aug. was defeated at Campomorto by Roberto Malatesta, papal condottiere, and peace was obtained on that side on 24 Dec. 1482. Instead relations grew embittered with Venice, which aimed at seizing Ferrara. Sixtus IV launched the interdict against Venice on 24 May 1483 and allied himself with Ferrara and with Mantua; the Peace of Bagnolo (7 Aug. 1484) between Milan and Venice put an end to these struggles. But not even internally did Rome know how to keep itself at peace, because of the turbulence of its citizens; indeed there were the bloody disputes between the Santacroce and the Della Valle, complicated by those between the Orsini and the Colonna; the latter opposed by Count Giacomo Riario; the execution of the protonotary Lorenzo Colonna, head of his house (30 June 1484) and fierce rival of Riario, did not suffice to extinguish the discords.
Sixtus IV celebrated the Jubilee in 1475; but he was not able to promote an effective reform in the Church, and under his pontificate abuses long since deplored in ecclesiastical discipline matured ever more. Sixtus IV did not fail to take measures for the development of agriculture around Rome and for the city's grain supply; but to raise money he multiplied venal offices and filled the Curia with new officials. He was very munificent toward the Vatican Basilica, built the Sistine or new Chapel, inaugurated in 1483, rebuilt the churches of the SS. Apostoli and of his Order, of St. Mary of the People for the Augustinians, of St. Mary of Peace with the cloister for the Canons Regular; he provided for the arrangement of the Vatican Library. For the convenience and adornment of the city he rebuilt the Ponte Sisto and set about making many streets wide, clean and paved, removing ugliness and obstacles. In this he provoked the emulation of curials and cardinals in building palaces; sumptuous funeral monuments invaded the churches; painters, sculptors, architects among the most illustrious, flocked from every side, were able to give new luster to the city, which was being renewed according to the canons of Renaissance art, and studies too found ever greater favor. Sixtus IV died on 12 Aug. 1484. The most beautiful bronze tomb by Pollaiolo received his remains. - See plate XLVIII.
Bibliography11 works
Pio Paschini
SIXTUS IV, POPE - Gabriele Zerbi offers to Sixtus IV his Quaestiones Metaphysicae. Miniature adorning the dedication copy to Sixtus IV printed on parchment in Bologna by the press of Giov. Valbech and Endrico van Haarlem, 1 Dec. 1482 - Vatican Library, membr. II, 19.
pp. 119-29, 152-36; R. Valentini-G. Zucchetti, Codice topogr. della città di Roma, II, ibid. 1942, pp. 22, 63; M. Combet-Farnoux, s. v. in DACL, XV, coll. 1501-15.
Agostino Amore