Ippolito dei Medici (1511-1535) was the natural son of Giuliano, Duke of Nemours. While still a baby, he was given into the care of his uncle, Pope Leo X (Giovanni Medici). The pope's cousin, who succeeded him to become Pope Clement VII, made Ippolito a cardinal in 1529. His unusual attire is a reference to the part he played in the defence of Hungary against the Turks, shortly before this portrait was created.