Vases made to celebrate the re-inauguration of the Panathenaic Games in Athens in the 560s B.C. provide a fixed date for tracing the development of sixth-century pottery styles. See John Boardman, The Greeks Overseas (Baltimore: Penguin Books, 1964), pp. 29–30. For the method of determining absolute dates according to the Common Era (B.C./A.D.) from the data given in ancient Greek texts, see Elias Joseph Bickerman, Chronology of the Ancient World, (Ithaca, New York: Cornell University Press, 1968), pp. 80–86.