 The Seleucid empire's cavalry were placed in units of "oulamoi" and then into divisions of "ilai".Other than the usual auxiliary, citizen and militia cavalry units, the main elite cavalry units of the Seleucids were the "Agema" and the "Hetairoi" ("Companions").The "Hetairoi" were the standing elite cavalry unit of the Seleucid army, serving both in peace and war.