Portrait of Isabella de' Medici Orsini (?)

The question mark in the title is honest. This portrait is only tentatively identified as Isabella de' Medici, the cultured daughter of Cosimo the First, and its date of 1587 falls after her death, so it may be a posthumous likeness or another woman entirely. Isabella died in 1576 at a Medici villa. The court called it a sudden illness, while the widespread account, then and since, holds that her husband Paolo Giordano Orsini had her strangled. Unlike her brothers and sisters, she left no grand state portrait of the standard court type, an absence some historians read as a deliberate dimming of her memory after her death.