Cosimo was but a boy, and much addicted to field sports.
Guicciardini therefore reckoned that, with an assured income of 12,000 ducats, the youth would be contented to amuse himself, while he left the government of Florence in the hands of his Vizier.[9] But here the wily politician overreached himself.

Cosimo wore an old head on his young shoulders.

With decent modesty and a becoming show of deference, he used Guicciardini as his ladder to mount the throne by, and then kicked the ladder away.

The first days of his administration showed that he intended to be sole master in Florence.

Guicciardini, perceiving that his game was spoiled, retired to his villa in 1537 and spent the last years of his life in composing his histories.