the ratio between the number of men needed and the whole number available, the officers drew from each tribe a number proportionate to its capacity.[459] It would agree well with all the known facts to suppose that the addition of the second and third ratings, followed by a more thorough organization of the light troops, belongs to the early republic (509-387),[460] when Rome needed all her strength in her life and death struggle with hostile neighbors. At the same time the purchase of armor and the increased burden of military duty would help account for the desperate economic condition of the poorer peasants of that epoch. The proportions of the five ratings—20-15-10-5-2½ or 2—to be discussed hereafter,[461] suggest an explanation of their origin. It would be reasonable to assume that the normal holding of the well-to-do citizen was a twenty-iugera lot and that the Servian phalanx was composed of possessors of that amount, the light-armed being their sons and others distinctly inferior in wealth. In course of a few generations as the population grew, with no corresponding territorial expansion or colonization or industrial development, and with only a limited conversion of waste to arable land, many of the lots became divided and subdivided. The result was a weakening of the phalanx at a time when the state was in the most pressing need of military resources. The institution of the five ratings as a basis for the reorganization of the army was a temporary expedient for meeting the crisis, to be superseded not long afterward by a better system founded on military pay. In all probability the introduction of the five ratings, or at least the beginning of the movement in that direction, should be closely connected with the institution of the censorship in 443 or 435.[462] The supposition would give us a sufficient reason for the creation of this new office at that time, and the strengthening of the army would explain the success of the Romans in the wars immediately following.