In the spring of 1576 Bianca Buonaventuri gave out that she was enceinte and began forthwith her preparations for accouchement.  She left her palace in the Via Maggio, under the shadow of the Pitti Palace, and took up her abode in the Casino of the Orte Oricellari, which she had lately purchased from the family of Rucellai, and surrounded herself with confidential friends and attendants.

The denouement came on 29th August, when the Grand Duke was informed by Bianca’s surgeon-accoucheur, that she had been delivered of a child—­a boy!  Francesco was almost frantic with delight, and he hastened to his beloved Bianca’s bedside.  Picking up his child, he fondled him tenderly and almost smothered him with kisses, and at once gave orders for a ceremonial baptism.  Antonio, he called him—­after the kindly patron saint of that auspicious day—­when he personally handed the child to the Archbishop at the font.

The Grand Duchess was inexpressibly shocked, she refused to see her husband, shut herself up in her own apartments, and demanded an escort to Vienna!  The news was not long in reaching Rome, and it made Cardinal Ferdinando furious.  In a moment all the blandishments of “the Venetian” were dissipated; the better terms lately established in Florence were renounced, and the angry Prince, in unmeasured language, asserted that the child was not Francesco’s.

He knew well enough that what had come to pass, unless unchallenged, would imperil his presumptive title.  First it was sought to throw doubt upon Bianca’s actual maternity, and next to secure the person of the little boy.

Bianca and Antonio, under a strong guard, were sent off to Pratolino, hers and Francesco’s best-loved retreat—­they had together planned its beauties.  There, during her make-believe convalescence, she came to consider the very serious nature of her love’s stratagem, and she determined to make a full confession to her lover.  The Grand Duke was thunderstruck, but at once he recognised the emphatic importance of secrecy; for, as Vincenzio Borghini quaintly said:  “Florence was the greatest market in the world for tissues and materials of all kinds, and full of evil eyes, and ears, and tongues!” Meanwhile Ferdinando had not let the water run under the Arno bridges for nothing.  He discovered the surgeon-accoucheur who had attended Madonna Bianca—­one Giovanni Gazzi.  He maintained the fact of the confinement, but incidentally named the wet nurse, Giovanna Santi.  This woman admitted that she had been instrumental in the introduction into Madonna Bianca’s chamber of the newly-born son of a reputable woman, who lived with her husband behind the Stinche.

No trace could be found of these humble parents of Francesco’s supposititious child, and all Ferdinando’s enquiries were fruitless.  Many were the tales rife, in and out of the palaces and markets, but neither the Grand Duke nor Bianca took any steps to refute them, and after being, as usual, a nine days’ wonder, the subject dropped, apparently.