I. (Κλεόμβροτος), the 23rd king of Sparta, of the Agid line, was the son of Pausanias. He succeeded his brother AGESIPOLIS I. in the year 380 B. C., and reigned nine years. After the deliverance of Thebes from the domination of Sparta [PELOPIDAS], Cleombrotus was sent into Boeotia, at the head of a Lacedaemonian army, in the spring of 13. 100.378, but he only spent sixteen days in the Theban territory without doing any injury, and then returned home, leaving Sphodrias as harmost at Thespiae. On his march home his army suffered severely from a storm. His conduct excited much disapprobation at Sparta, and the next two expeditions against Thebes were entrusted to the other king, AGESILAUS II. In the year 376, on account of the illness of Agesilaus, the command was restored to Cleombrotus, who again effected nothing, but returned to Sparta in consequence of a slight repulse in the passes of Cithaeron. This created still stronger dissatisfaction : a congress of the allies was held at Sparta, and it was resolved to prosecute the war by sea. [CHABRIAS; POLLIS.] In the spring of 374, Cleombrotus was sent across the Corinthian gulf into Phocis, which had been invaded by the Thebans, who, however, retreated into Boeotia upon his approach. He remained in Phocis till the year 371, when, in accordance with the policy by which Thebes was excluded from the peace between Athens and Sparta, he was ordered to march into Boeotia. Having avoided Epaminondas, who was guarding the pass of Coroneia, he marched down upon Creusis, which he took, with twelve Theban triremes which were in the harbour; and he then advanced to the plains of Leuctra, where he met the Theban army. He seems to have been desirous of avoiding a battle, though he was superior to the enemy in numbers, but his friends reminded him of the suspicions he had before incurred by his former slowness to act against the Thebans, and warned him of the danger of repeating such conduct in the present crisis. In accusing Cleombrotus of rashness in fighting, Cicero (Off. 1.24) seems to have judged by the result. There was certainly as much hesitation on the other side. In the battle which ensued [EPAMINONDAS; PELOPIDAS] he fought most bravely, and fell mortally wounded, and died shortly after he was carried from the field. According to Diodorus, his fall decided the victory of the Thebans. He was succeeded by his son AGESIPOLIS II. (Xen. Hell. 5.4. §§ 14-18, 59, 6.1.1, 4.15; Plut. Pel. 13, 20-23, Ages. 28; Diod. 15.51-55; Paus. 1.13.2, 3.6.1, 9.13. §§ 2-4; Manso, Sparta, 3.1. pp. 124, 133, 138, 158.)