At least four of these children were born of Vannozza (or Giovannozza) dei Catanei, a Roman lady who was the Cardinal's mistress from about 1460 to 1486. The story that she was an orphan entrusted to his care and seduced by him is not reliable. Nothing is confidently known about her early years, but her epitaph has been discovered, and it honours her, not only for her "signal probity and great piety," but because she was the mother of Cæsar, Juan, Jofre, and Lucrezia Borgia. Pedro Luis and Girolama may have been born of an earlier mistress, but it is not at all certain. Vannozza, who married three times, is constantly mentioned, by the ambassadors, as Borgia's mistress. She had a handsome mansion near the Cardinal's palace and the Vatican, and she entertained there and in her country house long after Borgia became Pope and replaced her by a younger mistress. These monuments of parentage are almost the only evidences of the existence of Cardinal Borgia under Pius II. and Paul II. In 1471 a pious and learned Franciscan friar, Sixtus IV., assumed the tiara, and it is an indication of the strange temper of the times that under such a man the Papal Court became more corrupt than ever.[273] Sixtus vigorously restored the secular rule of the Papacy and encouraged the artistic and cultural development, but his nepotism was shameless and profoundly harmful. One of the nephews whom he drew from the obscurity of a Franciscan monastery and made a prince of the Church was Pietro Riario, who spent 260,000 ducats,[274] and within two years of his promotion wore out his life in the most flagrant dissipation. His immense palace, with its magnificent treasures, its five hundred servants in scarlet silk, and its prodigious banquets, was the home of every species of vice; and it is said that his chief mistress, Tiresia, flaunted eight hundred ducats' worth of pearls on her embroidered slippers. Another nephew was the sterner, though also immoral, Cardinal Giuliano della Rovere--also brought from a monastery--whom we shall know as Julius II. Other cardinals promoted by the friar-Pope were equally notorious for their indulgence and for the unscrupulous quest of money to sustain it.