History of acquisition and the first century in California -- Description of the artifact -- Pertinence of the head -- The inscription -- The Seven Sages -- The Tivoli Plato -- The Berkeley Plato and the Renaissance -- Portraits of Plato -- The Berkeley Plato and the Akademy -- Ribbons -- Plato and ribbons -- Why Plato and ribbons -- Conclusion -- Appendix A: The square-omicron and square-theta portrait herms from Tivoli -- Appendix B: Technical and scientific analysis / by John Twilley