(Λεωνίδας), king of Sparta, was son of the traitor, Cleonymus, and 28th of the Agids. He acted as guardian to his infant relative, Areus II., on whose death, at the age of eight years, he ascended the throne, about B. C. 256, being by this time considerably advanced in life. A great part of his earlier years he had spent in the courts of Seleucus Nicator and his satraps, and had even married an Asiatic wife, by whom he had two children. From this it is reasonable to suppose that he reversed the policy of his predecessors, who had cultivated a connection with Egypt: and it is at least an ingenious conjecture of Droysen's, that the adventurer, Xanthippus, who entered at this period into the Carthaginian service, and whom he identifies with the general of Ptolemy Euergetes in his war with Seleucus Callinicus, may have been one of those who, as favourers of the Egyptian alliance, were driven from Sparta by the party of Leonidas. (Droysen, Hellenismus, vol. ii. pp. 296, 347; comp. Arnold's Rome, vol. ii. p. 589.) The habits which Leonidas had contracted abroad, very different from the old Spartan simplicity, caused him to regard with strong dislike the projected reforms of Agis IV., and he laboured at first to counteract them by secret intrigues and by the slanderous insinuation that the object of Agis was to bribe the poor with the property of the rich, and thus to make himself tyrant of Sparta. When the measure of his colleague was actually brought forward, Leonidas opposed it with arguments ludicrously weak, but succeeded, nevertheless, in obtaining its rejection in the senate by a majority of one. It thus became necessary for the reformers to get rid of him, and accordingly the ephor Lysander revived an old law, which forbade a Heracleid to marry a foreigner, and affixed the penalty of death to a sojourn in a foreign land. There was also an ancient custom at Sparta, of which he took advantage to excite the stronger prejudice against Leonidas. Every ninth year the ephors sat in silence to observe the heavens on a clear and moonless night; and if a star was seen to shoot in a particular direction, it was interpreted as a sign of some offence against the gods on the part of the kings, who were therefore to be suspended from their office till an oracle from Delphi or Olympia should declare in their favour. Lysander professed to have seen the sign, and referred it to the displeasure of heaven at the illegal conduct of Leonidas. He also accused him, according to Pausanias, of having bound himself by an oath, while yet a boy, to his father Cleonymus, to work the downfall of Sparta. Leonidas, not venturing to abide his trial, took refuge in the temple of Athena Chalcioecus, where his daughter Cheilonis joined him. Sentence of deposition having been passed against him in his absence, the throne was transferred to his son-in-law, Cleombrotus; and the ephors of the succeeding year having failed in their attempt to crush Lysander and his colleague, Mandrocleidas, by a prosecution [see Vol. I. p.73], Leonidas went into exile to Tegea. * It is erroneously stated, in Vol. I. p. 6.91, that his daughter Cheilonis accompanied him thither. See Plut. Agis 17. When the misconduct of Agesilaus, the uncle of Agis, had led, not long after, to his restoration (B. C. 240), he listened to the entreaties of Cheilonis, and spared the life of her husband, Cleombrotus, contenting himself with his banishment; but he caused Agis to be put to death, though he owed his own life to the protection he had afforded him in his flight to Tegea. Archidamus, the brother of Agis, fled from Sparta: Agiatis, his widow, was forced by Leonidas into a marriage with his son, Cleomenes; and it seems doubtful whether the child Eurydamidas, her son by Agis, was allowed to bear the name of king. At any rate the whole of the royal power (such as it was, in a selfish oligarchy, of which he was the tool) remained with Leonidas; and Plutarch tells us that he utterly neglected public affairs, caring for nothing but a life of ease and luxury. He died about B. C. 236, and was succeeded by his son, Cleomenes III. (Plut. Agis, 3, 7, 10-12, 16-21, Cleom. 1-3; Paus. 3.6; Clinton, F. H. vol. ii. p. 217; Droysen, Hellenismus, vol. ii. pp. 295, 296, 384, &c., 445.)