Sixtus IV, born Francesco della Rovere (July 21, 1414 - August 12, 1484) was Pope from 1471 to 1484, essentially a Renaissance prince, the Sixtus of the Sistine Chapel where the team of artists he brought together introduced the Early Renaissance to Rome with a masterpiece. (Michelangelo's ceiling was added in a later phase.).
Pope Sixtus IV appoints Bartolomeo Platina prefect of the Vatican Library,
ca 1477 (fresco) (Vatican Museums)
He was born to a modest family in Albisola, near Savona, Liguria. He joined the Franciscan Order, an unlikely choice, and his intellectual qualities were revealed while he was studying philosophy and theology at the University of Pavia. He went on to lecture at many eminent Italian universities. He was made Minister General of the Franciscan order in 1464. In 1467 he was made a Cardinal by Pope Paul II.
With his election, and after some ineffective sorties against the Turks in Smyrna, where fund-raising energy was more successful than half-hearted attempts to storm Smyrna and some attempts at unification with the Russian Orthodox Church, he turned to temporal issues and dynastic considerations. Sixtus continued the fruitless arguing with Louis XI of France, who continued to uphold the Pragmatic Sanction of Bourges (1438), that provided royal consent to papal decrees before they were promulgated in France, a cornerstone of the independence of the Gallican Church that could never be shifted, while Louis maneuvered to replace Ferdinand I of Naples with a French prince, which the Pope as a princely strategist could not permit.
Like a number of Popes, Sixtus was guilty of nepotism. In the fresco (illustrated, left) he is accompanied by his Della Rovere and Riario nephews, not all of whom were made cardinals: the apostolic pronotary Raffaele Riario (on his right), the future pope Julius II (pontiff from 1503 to 1513) standing before him, and Girolamo Riario and Giovanni della Rovere behind the kneeling Platina, author of the first Humanist history of the Popes. In his territoral aggrandizement of the Papal States his nephew Cardinal Raffaele Riario, for whom the Palazzo della Cancelleria was constructed, was a leader in the 1478 failed "Pazzi conspiracy" to assassinate Lorenzo de' Medici and his brother and replace them Florence with the other nephew, Girolamo Riario. The archbishop of Pisa, a main organizer of the plot, was hanged on the walls of the Florentine Palazzo della Signoria, and Sixtus replied with an interdict and two years' of war with Florence. He also encouraged the Venetians to attack Ferrara, which he wished to obtain for another nephew. The angered Italian princes allied to force Sixtus to make peace, an act which annoyed Sixtus immensely.
As a temporal prince, who constructed stout fortresses in the Papal States Sixtus committed himself rather scandalously to Venice's aggression against the duchy of Ferrara, which he incited the Venetians to attack in 1482; their combined assault was interdicted by an alliance of Sforza Milan, Medici Florence, and the King of Naples, his hereditary ally and usual strongarm of the Papacy. For refusing to desist from the very hostilities that he had instigated (and for being a dangerous rival to Della Rovere Papal ambitions in the Marche), Sixtus placed Venice under interdict in 1483.
Sixtus consented to the Spanish Inquisition issued a bull in 1478 that established an Inquisitor in in Seville, under political pressure from Ferdinand of Aragon, who threatened to withhold military support from his kingdom of Sicily. Nevertheless, Sixtus quarrelled over protocol and perogatives of jurisdiction, was unhappy with the excesses of the Inquisition and took measures to condemn the most flagrant abuses in 1482. In ecclesiastical affairs, Sixtus IV instituted the feast (December 8) of the Immaculate Conception of the Virgin Mary. He formally annulled (1478) the reformist decrees of the Council of Constance.
As a civic patron in Rome, even the anti-papal chronicler Stefano Infessura agreed that Sixtus must be admired. The Sistine Chapel was sponsored by Sixtus, as was the Sistine Bridge, to facilitate the integration of with the heart of old Rome. He also had San Vitale rebuilt in 1475, and refounded, enriched and enlarged the Vatican Library. He had Regiomontanus attempt the first sanctioned reorganization of the Julian calendar and called Josquin des Prez to Rome for his music. His bronze funerary monument in St Peter's Basilica, like a giant casket of goldsmith's work, is by Antonio Pollaiuolo
The cardinals of Sixtus IV
At the death of Sixtus IV, the conclave of cardinals that met to elect his successor numbered 32 surviving cardinals, a greater number than at any time since the close of the twelfth century, excepting perhaps for the multiplied rival cardinalates of the Great Schism (1378 - 1417). Of the 32, only three cardinals survived from before Paul II (1464 - 71): the two nephews of Calixtus III (1455 - 58), Rodrigo and Luis Borgia, and the nephew of Pius II (1458 - 64), Francesco di Nanni Todeschini de' Piccolomini. Six further cardinals survived from the pontificate of Paul II: Thomas Bourchier, Oliviero Caraffa, Marco Barbo, Jean Balue, Giovanni Battista Zeno and Giovanni Michiel. The remaining 23 had been made cardinals by Sixtus IV, and the roster of the princely houses of Italy, France and Spain will be familiar to any reader of Renaissance history: Giuliano della Rovere, Stefano Nardini, Pedro Gonsalvez de Mendoza, Giovanni Battista Cibo (soon to be Pope Innocent VIII), Giovanni Arcimboldi, Philibert Hugonet, Giorgio da Costa, Charles de Bourbon l'ancien, Pierre de Foix le jeune, Girolamo Basso della Rovere, Gabriele Rangoni, Pietro Foscari, Juan of Aragon, Raffaele Sansoni Riario, Domenico della Rovere, Paolo Fregoso, Giovanni Battista Savelli, Giovanni Colonna, Giovanni Conti, Juan Moles de Margarit, Giangiacomo Sclafenati, Giovanni Battista Orsini and Ascanio Maria Sforza-Visconti.