All who did not belong to the equestrian centuries were again divided into those who possessed upwards of 12,500 asses, and the poorer ones, whose census did not reach that sum. The former were distributed into five classes: in these there were no patricians whatever, but all the plebeians whose census amounted to the sum fixed, and the _ærarii_, that is to say, those who were not in the tribes, but had an income which made them equal to those who were. The ærarians are now what the plebeians had been before: as soon as they acquire landed property, they enter into the tribes. In the first class were all those who in landed estates, metals, agricultural implements, beasts of draught, slaves, flocks, herds, and horses, possessed as much property as was valued at 100,000 asses and upwards: these were divided into eighty centuries. All who were above sixteen and under forty-five, were reckoned among the _juniores_; from forty-five to sixty, among the _seniores_. In Sparta, the obligation to military service lasted until the sixtieth year; at Rome, it was in the case of the _seniores_ limited to the defence of the walls only. As regards numerical proportion, the _seniores_ certainly were not half of the whole:--men of that age, according to what is a favourable average of life in the south, would be scarcely a fourth part, or more exactly two-sevenths;--all who were alive above forty-six, might have been about the half. There is every probability that in those times all the rights and obligations of citizenship ceased at the sixtieth year. In Greece, a greater value was placed on the capacity of old people; among the Melians, the whole government was placed in the hands of the aged men above sixty. Although the _seniores_ amounted indeed to not more than about half the number of the _juniores_, yet they had quite as many votes, and may also have been called up first to give their suffrages. The remainder were divided into four classes, of 75,000, 50,000, 25,000, and 12,500 asses. Of these, the second, third, and fourth had twenty centuries each; the fifth had thirty. A hundred thousand asses was no great fortune; it was pretty nearly equivalent to ten thousand drachmas of Athens, an as being worth about a stiver and a half.[77] At the levies, each century had to serve according to a fixed rate; so that those which contained but a small number, had to do more military duty than the larger ones. The conscription was from tribes and centuries combined. In the thirty tribes, one man was always called from each century of the _juniores_, from each century therefore thirty men. Each following class had to furnish more troops; and that in such a manner, that when the first supplied a single contingent, the second and third were to send double ones, and the fourth again only a single one, employed as a javelin corps. The fifth also served with a double contingent.