History of the Peloponnesian War

Thucydides

Thucydides. The Peloponnesian War. London, J. M. Dent; New York, E. P. Dutton. 1910.

After this they joined battle, the Argives and their allies advancing with haste and fury, the Lacedaemonians slowly and to the music of many flute-players—a standing institution in their army, that has nothing to do with religion, but is meant to make them advance evenly, stepping in time, without breaking their order, as large armies are apt to do in the moment of engaging.