[3] At the age of fifteen she fell in love with Pietro Bonaventuri, a young Florentine clerk in the firm of Salviati family, and on 28 November 1563 escaped with him to Florence, where they were married.

Francesco and Joanna then produced a son, Grand Prince Philip de' Medici, in 1577; the child survived the perilous months of early infancy, and Bianca's hopes of being anything more than a favoured mistress seemed dashed.

The Venetian government now put aside its resentment and was officially represented at the magnificent wedding festivities, for it saw in Bianca Cappello an instrument for cementing good relations with Tuscany.

There would be no more children born of the relationship, and Bianca was aware that, if her husband were to die before her, she was lost, for his family, especially his brother Cardinal Ferdinand, hated her bitterly, as an adventuress and interloper.

Francesco immediately began working on securing the succession for his remaining son, Antonio, having him legitimated and declared heir apparent, with the support of Philip II of Spain.

Bianca Cappello, portrayed by Margaret Rawlings, was also the focal character of the Clifford Bax play The Venetian which in 1931 debuted on the West End stage and - subsequent to a tryout engagement in Chicago - made a short-lived transfer to Broadway.