Apollo is the god of measure. “Captain of Sevens,” his cithara brought seven-stringed order to music and seven-walled order to Thebes. As god of measure, symmetry informs the myth describing his birth: amid the Cycladic islands (which the Greeks considered a circle surrounding Delos) four adamantine columns bore Delos above the foam as Leto gave birth to the shining god. And, as in the birth of the Greek god of measure, so also in the emergence of the Greek world: a strict symmetry prevails in the myth describing how the omphalos, the earth's navel stone, came to be at the locus of what was to become Apollo's sacred seat. Zeus, it was told, freed two eagles from the ends of the earth, their paths crossing at the earth's center, at Delphi. The symmetric image of this aerial encounter over the terrestrial center suggests schematically the Apolline triad: two tensional extremes and, at the point of balance, a mediating mean.