Cosimo had decided that she was not to take up residence in Rome with Paolo. He decreed that Paolo would live by himself in Rome and would come to Florence when he wished to see his wife. Cosimo's decision was partly financial, for if Isabella left Florence, and her dowry went with her, Cosimo would be placing her fiscal well-being in the hands of Paolo, whom he did not trust to make wise decisions. Paolo was heavily dependent upon Cosimo's largesse and was not in a position to object to his father-in-law's decision. Yet Coosimo's desire for Isabella to remain in Florence was not solely a monetary issue. He did not want to let his favourite daughter go. With this decision, Cosimo was about to give Isabella, only just turned sixteen, a rare gift, one worth more than the 5,000 scudi worth of wedding jewels she received: a particular kind of independence that would give Isabella all the protection of a married woman, combined with the kind of freedom from spousal authority experienced by very few women of her day.
-- Caroline P. Murphy