Agis succeeded his father as king in 245 BC, at around the age of 20, and reigned four years. The interest of his reign, however, derived from the domestic crisis of Sparta at the time of his succession. According to sources, the influx of wealth and luxury, with their concomitant vices, led to the Spartan way of life degenerating from the ancient simplicity and severity of manners, and an extreme inequality in the distribution of wealth. Fewer than 700 families of the genuine Spartan stock (i.e. full citizens or homoioi) remained, and in consequence of the innovation introduced by Epitadeus, who procured a repeal of the law which secured to every Spartan head of a family an equal portion of land, the landed property had passed into the hands of very few individuals, so that fewer than 100 Spartan families held estates, while the poor were greatly burdened with debt.
Agis' program was in four points:
cancellation of debts: or more precisely, mortgages taken out on citizens' klaros (plot of land), as citizens often got into debts to pay for their contribution to the syssitia, and many had lost their status when the burden became too high.
redistribution of land: civic lands were redistributed in equal shares between Spartan citizens, former citizens who had lost their status because they could not afford the syssitia, periokoi, and even foreigners—probably mercenaries living in Laconia. In total, Agis created 4500 new lots of land for his new civic body: 700 for the remaining citizens, about 2000 for the degraded citizens, and the rest between periokoi and mercenaries.
restoration of the agoge, the rigorous military education in Sparta, which had disappeared after the late 270s.
restoration of the original syssitia, the collective messes, which had evolved into lavish banquets.
Agis, who from his earliest youth had shown his attachment to the ancient discipline, undertook to reform these abuses, and re-establish the institutions of Lycurgus. To this end he proposed the abolition of all debts and a new partition of the lands. Another part of his plan was to give landed estates to the Perioikoi capable of bearing the arms, and to the Metic women, "who had a beautiful appearance and were in prime of their life". His schemes were warmly seconded by the poorer classes and the young men, and as strenuously opposed by the wealthy. He succeeded, however, in gaining over three very influential persons: his uncle Agesilaus (a man of large property, but who, being deeply involved in debt, hoped to profit by the innovations of Agis), Lysander (a descendant of the victor of Aegospotami) and Mandrocleides. Having arranged for Lysander to be elected one of the six ephors, he laid his plans before the senate. He proposed that the Spartan territory should be divided into two portions, one to consist of 4500 equal lots, to be divided amongst the Spartans, whose ranks were to be filled up by the admission of the most respectable of the Perioikoi and resident aliens; the other to contain 15,000 equal lots, to be divided amongst the remaining Perioikoi.
The senate could not at first come to a decision on the matter. Lysander, therefore, convened the assembly of the people, to whom Agis submitted his measure, and offered to make the first sacrifice, by giving up his own lands and money, telling them that his mother, Agesistrate, and grandmother, who were both possessed of great wealth, with all his relations and friends, would follow his example. His generosity drew the applause of the multitude. The opposite party, however, headed by Leonidas II, Agis' Agiad co-monarch, who had formed his habits at the luxurious court of Seleucus II Callinicus, got the senate to reject the measure, though only by one vote. Agis decided to rid himself of Leonidas. Lysander accordingly accused him of having violated the laws by marrying a stranger and living in a foreign land. Leonidas was deposed, and was succeeded by his son-in-law, Cleombrotus, who cooperated with Agis.
