With respect to the latter coterie, its influence was vastly augmented by the assassination of Pietro Buonaventuri in 1572.  Duchess Isabella gave her whole heart’s support to the beauteous young widow.  She wrote to her the most affectionate letters, in one of which, if not in more, she says she loves Bianca “more than sister,” and bids her retain her position as “the loving helper of my brother.”

Bianca heartily returned her “more than a sister’s” affection, and she repeatedly spoke of Duchess Isabella in her letters to her cousins in Venice.  “I had,” she says, for example, on 17th July 1574, “the illustrious Domina Isabella to dine with me in my garden, and with her came my good friends her brother Don Piero and his young wife....”  Beautiful, accomplished, and light-hearted, Isabella and Bianca were the dearest and most constant of companions.  They lived apparently only for admiration and adulation, but the Duchess’ position was infinitely more free and unconventional than that of the Venetian:  the latter lived for one man’s love alone—­Francesco—­Isabella dispensed her favours where she willed!

Duke Paolo grew suspicious of his wife’s liberty of action.  His protests, at first couched in deprecatory language, were met with girlish insouciance; but, when he began to complain arrogantly, Isabella replied with spirit and determination.  His jealous reprimands were met by like charges and, truth to tell, there was not a pin to choose between the two.

The Grand Duke Cosimo before his death in 1574, and the Grand Duke Francesco, were alike irritated by Bracciano’s cool, calculating conduct; and both upheld Isabella against her husband’s ill-humour and harsh judgments.  Duke Paolo, however, kept his own counsel, and by means of spies discovered that Troilo d’Orsini’s monthly reports were at least open to doubt as to their truthfulness with respect to his wife’s conduct in private.  Matters, however, drifted—­he was too intent upon his own affairs in Rome and elsewhere to disturb rudely the state of things at Poggio Baroncelli.

His suspicions at length were brusquely confirmed, and the uneasy peace of evil deeds was broken by portentous news from Florence.  A courier in his pay arrived one evening, in July 1576, breathless, at the Bracciano Palace, with the intelligence that the trusty chamberlain had stabbed to the heart an attractive young page, Lelio Torello, attached to the household of the Grand Duke; and had, moreover, at once taken flight precipitately from the Villa!

Bracciano knew exactly what this purported—­young Torello was a lover of his wife as well as Troilo d’Orsini!  Without a moment’s delay, he started off for Florence to tax the Duchess with unfaithfulness.  At the Porta Romana he was staggered by the news which greeted him—­Piero de’ Medici had killed his wife, Eleanora de Garzia de Toledo, at Cafaggiuolo!