CAPPELLO, BIANCA (1548-1587), grand duchess of Tuscany, was the daughter of Bartolommeo Cappello, a member of a rich and ancient Venetian house, and celebrated for her great beauty. After a runaway marriage with Pietro Bonaventuri, a poor Florentine clerk, she became the mistress of Francesco, son and heir of the grand duke Cosimo de' Medici, who succeeded his father in 1574. Her husband having been murdered in Flor ence in 1572, and Francesco's wife having died in 1578, Bianca was married to him, the wedding being publicly announced on June 1o, 1579. In Oct. 1587 both she and her husband died within a few days of each other in circumstances that at first gave rise to suspicions of poisoning. Colic, however, would seem to have been the real cause of their deaths.