The early Pagan army consisted mainly of conscripts raised just prior to or during the times of war. Although historians believe that earlier kings like Anawrahta must have had permanent troops on duty in the palace, the first specific mention of a standing military structure in the Burmese chronicles is 1174 when Sithu II founded the Palace Guards—"two companies inner and outer, and they kept watch in ranks one behind the other". The Palace Guards became the nucleus round which the mass levy assembled in war time. Most of the field levy served in the infantry but the men for the elephantry, cavalry, and naval corps were drawn from specific hereditary villages that specialised in respective military skills. In an era of limited military specialisation, when the number of conscripted cultivators offered the best single indication of military success, Upper Burma with a greater population was the natural centre of political gravity.