the 31st king of Sparta of the Agid line, was the son of Leonidas II. After the death of Agis IV., B. C. 240, Leonidas married his widow Agiatis to Cleomenes, who was under age, in order, as it seems, to bring into his family the inheritance of the Proclidae. Agiatis, though at first violently opposed to the match, conceived a great affection for her husband, and she used to explain to him the principles and designs of Agis, about which he was eager for information. Cleomenes was endowed, according to Plutarch, with a noble spirit; in moderation and simplicity
The first movement of Cleomenes was to seize suddenly and by treachery the Arcadian cities, Tegea, Mantineia, and Orchomenus, which had recently united themselves with the Aetolians, who, instead of resenting the injury, confirmed Cleomenes in the possession of them. The reason of this was, that the Aetolians had already conceived the project of forming an alliance with Macedonia and Sparta against the Achaean league. It is probable that they even connived at the seizure of these towns by Cleomenes, who thus secured an excellent position for his operations against the league before commencing war with it. Aratus, who was now strategos, at last perceived the danger which threatened from Sparta, and, with the other chiefs of the Achaean league, he resolved not to attack the Lacedaemonians, but to resist any aggression they might make. About the beginning of the year 227 B. C., Cleomenes, by the order of the Ephors, seized the little town of Belbina, and fortified the temple of Athena near it. This place commanded the mountain pass on the high road between Sparta and Megalopolis, and was at that period claimed by both cities, though anciently it had belonged to Sparta. Aratus made no complaint at its seizure, but attempted to get possession of Tegea and Orchomenus by treachery. But, when he marched out in the night to take possession of them, the conspirators, who were to deliver up the towns, lost courage. The attempt was made known to Cleomenes, who wrote in ironical terms of friendship to ask Aratus whither he had led his army in the night ? " To prevent your fortifying Belbina," was the reply. " Pray then, if you have no objection," retorted Cleomenes, " tell us why you took with you lights and scaling ladders." By this correspondence Aratus found out with whom he had to do. The Spartans, on the other hand, were satisfied with the important advantage which they had gained in the fortification of Belbina; and Cleomenes, who was in Arcadia with only three hundred foot and a few horse, was recalled by the Ephors. His back was no sooner turned than Aratus seized Caphyae, near Orchomenus. The Ephors immediately sent back Cleomenes, who took Methydrion, and made an incursion into the territories of Argos. About this time Aristomachus succeeded Aratus as strategos of the Achaean league (in May, 227, B. C.), and to this period perhaps should be referred the declaration of war against Cleomenes by the council of the Achaeans, which is mentioned by Polybius. Aristomachus collected an army of 20,000 foot and 1000 horse, with which he met Cleomenes near Palantium; and, though the latter had only 5000 men, they were so eager and brave that Aratus persuaded Aristomachus to decline battle. The fact is, that the Achaeans were never a warlike people, and Aratus was very probably right in thinking that 20,000 Achaeans were no match for 5000 Spartans. But the moral effect of this affair was worth more than a victory to Cleomenes. In May, 226, Aratus again became strategos, and led the Achaean forces against Elis. The Eleans applied to Sparta for aid, and Cleomenes met Aratus on his return, at the foot of Mount Lycaeum, in the territory of Megalopolis, and defeated him with great slaughter. It was at first reported that Aratus was killed; but he had only fled; and, having rallied part of his army, he took Mantineia by a sudden assault, and revolutionized its constitution by making the metoeci citizens. The effect of this change was the formation of an Achaean party in the town.
Cleomenes had not yet taken any open steps against the Ephors, though he could not but be an object of suspicion to them; they were however in a difficult position. The spirit of Agis still lived in the Spartan youth; and Cleomenes, at the head of his victorious army, was too strong to be crushed like Agis. Secret assassination might have been employed--and when was a Spartan ephor heard of who would have scrupled to use it ?--but then they would have lost the only man capable of carrying on the war, and Sparta must have fallen into the position of a subordinate member of the Achaean league. They appear, however, to have taken advantage of the loss of Mantineia to make a truce with the Achaeans. (Paus. 8.27.10.) Cleomenes now took measures to strengthen himself against them. These measures are differently represented by Phylarchus, the panegyrist of Cleomenes, whom Plutarch seems on the whole to have followed, and by Polybius and Pausanias, who followed Aratus and other Achaean writers. At the death of Agis, his infant son, Eurydamidas, was left in the hands of his mother, Agiatis; and Archidamus, the brother of Agis, fled into Messenia, according to the statement of Plutarch, which, from the nature of the case, is far more probable than the account of Polybius (5.37.2, 8.1.3), that Archidamus fled at a later period, through fear of Cleomenes. Eurydamidas was now dead, poisoned, it was said, by the Ephors, and that too, according to Pausanias (2.9.1), at the instigation of Cleomenes. The falsity of this last statement is proved by the silence of Polybius, who never spares Cleomenes, but it may serve to shew how recklessly he was abused by some of the Achaean
Having secured the aid of his father-in-law, Megistonus, and of two or three other persons, he first weakened the oligarchical party by drafting many of its chief supporters into his army, with which he then again took the field, seized the Achaean cities of Heraea and Asea, threw supplies into Orchomenus, beleaguered Mantineia, and so wearied out his soldiers, that they were glad to be left in Arcadia, while Cleomenes himself marched back to Sparta at the head of a force of mercenaries, surprised the Ephors at table, and slew all of them, except Agesilaus, who took sanctuary in the temple of Fear, and had his life granted afterwards by Cleomenes. Having struck this decisive blow, and being supported not only by his mercenaries, but also by the remains of the party of Agis, Cleomenes met with no further resistance. He now propounded his new constitution, which is too closely connected with the whole subject of the Spartan polity to be explained within the limits of this article. All that can be said here is, that he extended the power of the kings, abolished the Ephorate, restored the community of goods, made a new division of the lands, and recruited the body of the citizens, by bringing back the exiles and by raising to the full franchise the most deserving of those who had not before possessed it. He also restored, to a great extent, the ancient Spartan system of social and military discipline. In the completion of this reform he was aided by the philosopher Sphaerus. The line of the Proclidae being extinct, he took his brother Eucleidas for his colleague in the kingdom. In his own conduct he set a fine example of the simple virtue of an old Spartan.
From this period must be dated the contest between the Achaeans and Cleomenes for the supremacy of Greece, which Polybius calls the Cleomenic war, and which lasted three years, from B. C. 225 to the battle of Sellasia in the spring of B. C. 222. For its details, of which a slight sketch is given under ARATUS, the reader is referred to the historians. Amidst a career of brilliant success, Cleomenes committed some errors, but, even if he had avoided them, he could not but have been overpowered by the united force of Macedonia and the Achaean league. The moral character of the war is condensed by Niebuhr into one just and forcible sentence :-- " Old Aratus sacrificed the freedom of his country by an act of high treason, and gave up Corinth rather than establish the freedom of Greece by a union among the Peloponnesians, which would have secured to Cleomenes the influence and power he deserved." (History of Rome, iv. p. 226.)
From the defeat of Sellasia, Cleomenes returned to Sparta, and having advised the citizens to submit to Antigonus, he fled to his ally, Ptolemy Euergetes, at Alexandria, where his mother and children were already residing as hostages. Any hope he might have had of recovering his kingdom by the help of Ptolemy Euergetes was defeated by the death of that king, whose successor, Ptolemy Philopator, treated Cleomenes with the greatest neglect, and his minister, Sosibius, imprisoned him on a charge of conspiracy against the king's life. Cleomenes, with his attendants, escaped from prison, and attempted to raise an insurrection against Ptolemy, but finding no one join him, he put himself to death. (B. C. 221-220.) His reign lasted 16 years. He is rightly reckoned by Pausanias (3.6.5) as the last of the Agidae, for his nominal successor, Agesipolis III., was a mere puppet. He was the last truly great man of Sparta, and, excepting perhaps Philopoemen, of all Greece.
(Plutarch, Cleom., Arat.; Polyb. ii. v., &c.; Droysen, Geschichte der Hellenismus, vol. ii. bk. 2.100.4; Manso, Sparta, vol. iii.)[P.S]