This proud young aristocrat is Lodovico Capponi (b. 1533), a page at the Medici court. As was his custom, he wears black and white, his family's armorial colors. His right index finger partially conceals the cameo he holds, revealing only the inscription sorte (fate or fortune) — an ingenious allusion to the obscurity of fate. In the mid 1550s Lodovico fell in love with a girl whom Duke Cosimo had intended for one of his cousins. After nearly three years of opposition, Cosimo suddenly relented, but he commanded that their wedding be celebrated within twenty-four hours.
Source: Art in The Frick Collection: Paintings, Sculpture, Decorative Arts, New York: Harry N. Abrams, 1996.