The earthquake Sparta experienced in 464/65 BC. strongly directed politics of the time by contributing to the rivalry between the Spartans and the Athenians and has been identified as a significant cause of Spartan oliganthropia, or shortage of Spartiate males. Thucydides writes that a single earthquake occurred and places the blame for the immediate slave revolt on the Messenian helots, whereas Diodorus refers to multiple earthquakes and blames the rebellion largely on the Laconian helots.
A comparison of Spartan military behaviour immediately before the earthquake and in the years following it reveals a decline in aggressiveness. Thucydides acknowledges that they were prepared to invade Attica in support of Thasos just prior to the earthquake. However, the Spartans were unwilling to invade Attica at the urging of Megabazus, even though a tremendous Athenian force was then engaged in Egypt (Thucydides 99; 1.109). Losses experienced in the battle fought for over sixty days at Tanagra in Boeotia (Thucydides 98; 1.108) may have also contributed to this change in behaviour. Regardless, a population problem existed arguably at the time of Pylos, where the Spartans were ready to sue for peace over a mere 120 Spartiates, and certainly by the time of Leuctra, where there were only 700 Spartiates altogether. The earthquake and subsequent revolt provides a finite time period in which Spartan behaviour changes, and a significant population decline could have occurred.
Can the decline of Spartan citizens be attributed to the earthquake alone. Diodorus' estimate of 20,000 deaths is a pointer towards that. If even half of the 20,000 were Spartans rather than helots or perioeci, this would have serious and immediate results and may be a reason why Sparta petitioned Athens for help at Ithome. Thucydides writes, "The chief reason that they asked for help was that the Athenians had the reputation of being good at siege operations" (95; 1.102). He assures the reader that the Spartans would have long since taken "the place (Ithome) by assault" if it were not for their lack of experience (Thucydides 95; 1.102). A. W. Gomme points out that not even the Athenians were especially good at sieges and argues that Thucydides meant "an assault. . . on a palisaded camp" rather than a typical siege of a walled fort (301; bk. 1, 102.1). He adds, "Sparta asked for help when in a difficult position and not simply in order to convert a slow siege into a quick assault" (301; bk. 1,.102.1). A major loss of life may have contributed to this "difficult position" which the Spartans would be unwilling to admit to the Athenians. Thucydides also has good reason to downplay a loss of Spartan numbers. As this precedes the Peloponnesian War, a small Spartan population would weaken his assertion "that the two sides were at the very height of their power and preparedness" (Thucydides 35; 1.1).
Sometime after the Peloponnesian War or early in the 4th C BC a law, the Epitadeus , was passed which altered the rules of the entitlement to land of the homoioi. Previously under Lycurgan law the kleros inherited by the Spartiate was inalienable, and this land along with the helots who worked it was the basis of the economic support of the homoioi. This new law permitted a Spartan to deed his land to any other Spartan during his lifetime and bequeath it in his will freely. It was to be done in the guise of a gift for a gift of equal value, but the gift could be money. The result was that over some time a minority began to possess the majority of the land while another minority though growing more numerous were without land (hypomeiones). Thus the number of Equals was reduced still further. This law and its operation could only have been brought about if the Lycurgan prohibition against coined money and its ownership by individuals was relaxed.
By the end of the war with Athens in 404 BC much Persian gold had been brought into Sparta as subsidies, and after victory Lysander brought 470 talents on his return to Sparta. Gyllipus who had been charged with the delivery of these subsidies was subsequently found to have had his fingers in the till and was tried and exiled.
For Sparta to maintain its position as the dominant Aegean power, maintain a fleet and a permanent presence abroad, the question of money would have to be settled. In a debate at Sparta in 404 a compromise was reached where the laws against private possession were upheld but were relaxed in the case of the state. However the machinery to enforce this was probably non-existent or too weak. The influx of annual tributes from the old Athenian Empire a sum of 1,000 talents per year was too much for the existing administration to cope with and the influences of corruption began to be felt. Many sought to enrich themselves, and there was no better way to do it than in the office of harmost where the use of extortion, corruption and bribery were rife. It was as harmost at Samos that Thorax made his fortune, he was eventually caught and executed. Clearchus at Byzantium was another example though he was only exiled.
These problems became even graver in the ensuing decades, the state was ready to act against individuals but could not cure the underlying causes and by Leuctra Sparta found herself without sufficient manpower due to economic problems and insufficient allies due to imperial corruption.
The defeat at Leuctra can be easily explained in purely military terms as early as 390 new tactics had caught the Spartans wrong footed, at Laecheum by Iphicrates at Tegyra by Pelopidas in 375 and in 371 Epaminondas adopted even newer tactics. But one defeat hover shattering cannot explain why Sparta was internally too weak to survive it as a great power. By Leuctra the Spartan army consisted of 'Equals', Perioicoi and a number of hypomeiones, the numbers of which are debatable. The neodamodeis served in separate units of whom there were a large number. The Spartans during their period of hegemony also deployed numbers of mercenary hoplites and peltasts. As seen the number of 'Equals' was declining thus the number of 'Unequals' by the same token would be rising. Although they did not belong to a kleros and could not pay their mess bills because they were landless they would still have been part of the Spartan army organization and training although without the full citizens rights. There were also a certain number of 'Spartans' who may have been adopted by 'Equals' and sponsored by them. As well as these there were those of military age, either sons with living fathers or younger brothers who could serve as a pool of reserves.
Lets look at the size of the army in the 5th and 4th centuries from the facts as given by the classical writers. At Plataea in 479 5,000 Spartiates and 5,000 Perioicoi served separately, Herodotus does not mention how they were organized except that there was a lochos of Pitane of unknown size included among the Spartans. After 371 the army is described as consisting of 12 units called lochoi by Xenophon. In between both Xenophon and Thucydides describe an army of 6 units but they differ on the name of the unit, mora or lochos.
In 425 the Spartans put 420 men onto Sphacteria drawn by lots from all of the lochoi. Those who surrendered were 120 Spartiates and 170 non-Spartiates (Perioicoi and Hypomeiones). In 418 at Mantinea Thucydides numbers the army at 3,072 on a 32 year call up consisting of 6 lochoi each of 4 pentekostys of 4 enomotiai, not enough to make sense of the battle. Xenophon mentions the mora first in 403 and in 390 and gives its strength at 600. At Nemea the strength of the army was 6,000 in 5 units. In his Lakedaimonian Politeia Xenophon describes an army of 6 mora consisting of 4 lochoi each of 2 pentekostys of 2 enomotiai. At Leuctra 4 mora were present on a 35 year call up and according to Xenophon only 700 were Spartiates. Now 700 Spartans could not make up 4 mora, so who were the rest? I believe the Perioicoi were not expected to serve outside the Peloponnese except as volunteers. Therefore the remainder must have been hypomeiones with Perioeci volunteers and that these served as part and parcel of the Spartan field army. The Perioicoi must have always been brigaded separately as attested by Xenophon in several passages where the Spartan field army had advanced beyond the frontier only to have to wait for the perioicic contingent. Pausanius in 395 specifically waited at Tegea for them and 8 years later Agesilaus sent some of the hippeis to hurry them up. Another objection to the supposition that both Spartans and Perioicoi were brigaded together is that they were amateurs and unaccustomed to the day to day training in tactics and drill. Thus Xenophon in his Politeia is describing a purely Spartan Mora undiluted by Perioicoi and Thucydides has in his description of the Spartan forces at Mantinea missed out one whole level of organization, the Mora and has given the numbers of the Spartans alone ignoring the Perioicoi.
When scholars talk of Spartan population decline they are not talking about the population of Lacedaemon which would have retained a healthy growth in the 5th and 4th centuries, the perioicic communities were as healthy as any other but of the decline in the number of Spartiates or 'Equals'. The losses from the earthquake of 465 were soon restored, the losses of 400 at Leuctra could be replaced. Economic factors and the loss of the Messenian kleros combined with a declining birth rate among Spartans caused by the laws of inheritance, a general unwillingness to produce children and the inadequacy of the public kleros were contributing factors in this decline. The loss of perioicic territories in Laconia and allies in the Peloponnese after Leuctra further reduced the pool from which Sparta could build an adequate force with which to play in the first division nor had she enough money to make up the difference by hiring enough mercenaries.
Equality was supposed to be secured by a land apportionment that assigned
9,000 equal lots to full Spartiates and 30,000 to the larger population of
perioikoi. The lots were defined not by size but by productivity. Scholars have
endlessly debated whether there ever was such an equal distribution and whether
it worked. On the whole, I think the evidence shows that equality of land was
the Spartan ideal, as it was in several other Dorian states originally. This
equal distribution impressed political theorists like Plato (D.M. MacDowell,
Spartan Law. Edinburgh: Scottish Academic Press, 1986).
The insistence upon equality created several problems. In the first place, it meant that those who became unequal, that is fell below a certain minimum standard of wealth, were no longer citizens, because they could no longer make their contribution to the common messes. Since Sparta refused to recruit new citizens from the perioikoi, this meant a steady diminution in the citizen body.
Some non-Spartiate boys admitted to troops and later to the men’s messes—mothakes: These might be children of foreigners like Xenophon, illegitimate sons of citizens, or sons of families that had lost their citizenship status, typically for lack of money. In general they could never become full citizens.
Obviously, a system in which lots are fixed will inevitably discourage large families. The optimum family size at Sparta must have been one boy—and no girls to pay dowries for. Greeks at this time did not typically practice abortion—though we hear of a mythical Spartan Queen who offered to abort her child, the future king of Sparta if a male, if Lycurgus would marry her—or expose healthy children. But various effective means of contraception were available. Let us suppose three generations of a 5th-century family in which only 1-2 sons are born to a married couple. What is the likelihood, after the Persian Wars and the Peloponnesian War, that the third generation has a male heir? Failing a male heir, property ended up in the hands of daughters, who if married took it out of the family but if single retained it, which tended to increase further the power and liberty of women.
So for all these reasons, Sparta was doomed, and after her defeat by Thebes at the Battle of Leuctra in 371 B.C., she lacked the manpower resources to recover her shattered prestige, and although in the 3rd century Agis IV and Cleomenes III tried to restore the old Sparta by promoting deserving periokoi to citizenship and redistributing the land, they were prevented from carrying out their reforms the first by internal opposition and the second by external opposition.
Aristotle has the benefit of hindsight. Had he lived 100 years earlier, when the Spartan system functioned reasonably well, he might have been a good deal less skeptical. He does say in a previous chapter that the Spartan model mixes, as a true politeia ought to, the elements of monarchy (the kings), oligarchy (the Council of elders), and democracy (the ephors and the assembly). Near the end of the Politics (VII.13), he grudgingly concedes them one great advantage: Their superiority does not lie in the fact that they have a different conception of what things are the greatest goods, but their conviction that these goods are to be obtained by applying the virtue of courage. That, at the very least, is a useful lesson to take from the Spartan model.