Pietro Buonaventuri vowed he would marry her, but the Ricci would have none of him; and he fell, one summer's night, under the very windows of his wife's bedchamber, pierced with twenty-five savage dagger thrusts. That same night--it was 27th August 1572--Madonna Cassandra was stabbed, in her own apartment, also twenty-five times, and two stark, mutilated corpses were mercifully borne away, in the dawn, by the brethren of the _Misericordia_, and given burial. Bianca, widowed, demanded at the hand of her princely lover justice for the spilling of her husband's blood; but, for answer, Francesco drew her gently to his heart and said: "The best thing I can do now, my own Bianca, is to make you, before long, Grand Duchess of Tuscany!" The Cardinal was keenly interested in this tragedy, not indeed that he took any part therein, but it had a distinct bearing upon his line of conduct, and he noted with apprehension the redoubling of Francesco's devotion to "the hated Venetian." Bianca, of course, was perfectly aware that she was the real cause of Ferdinando's animosity, in spite of his protestations of admiration and the like. She set about to unmask his real intentions and to circumvent his hypocrisy. Her methods were at once original and full of tact, for she disarmed his aggression by playing to his personal vanity and by furthering his lust for money. Not once, nor twice, but many times, did Bianca plead with Francesco for his brother, and always with success, and many a substantial sum of money was lodged in the Roman Medici bank at his disposal. Ferdinando began to realise that the only way to his brother's purse was by Bianca's favour, and he began to evince a distinctly amiable spirit in his relations with her. As marking the improvement in the situation, the Cardinal accepted an invitation to a family gathering at Poggio a Caiano in the autumn of 1575. The Grand Duchess Giovanna quite properly was the hostess, but Bianca Buonaventuri, who was installed in a Casino in the park, which Francesco had given her, and called "Villetta Bini," was of the party, the life and soul of all the entertainments. During the festivities Bianca managed to be _tête-à-tête_ with her brother-in-law in a secluded summer-house. The fascination of three years before was again transcendent. "The Venetian is irresistible," he said afterwards, "I cannot hate her, try how I will!" The truth was, he was madly in love, and he owned it, but his love was, after all, like the hot fumes of a lurid fire. The year 1576 was a black one in the annals of the Medici. Two beautiful and accomplished princesses of the ruling house were done to death by jealous, unfaithful husbands.