there was a leader in each row of a phalanx, and a rear rank officer, the "ouragos" (meaning tail-leader), who kept order in the rear. the hoplites had to trust their neighbours to protect them and in turn be willing to protect their neighbors; a phalanx was thus only as strong as its weakest elements. the effectiveness of the phalanx therefore depended on how well the hoplites could maintain this formation in combat and how well they could stand their ground, especially when engaged against another phalanx. for this reason, the formation was deliberately organized to group friends and family close together, thus providing a psychological incentive to support one's fellows, and a disincentive, through shame, to panic or attempt to flee. the more disciplined and courageous the army, the more likely it was to win – often engagements between the various city-states of greece would be resolved by one side fleeing before the battle. the greek word "dynamis", the "will to fight", expresses the drive that kept hoplites in formation.