Plutarch, Agis
Bernadotte Perrin, Ed.

3. When once the love of silver and gold had crept into the city, closely followed by greed and parsimony in the acquisition of wealth and by luxury, effeminacy, and extravagance in the use and enjoyment of it, Sparta fell away from most of her noble traits, and continued in a low estate that was unworthy of her down to the times when Agis and Leonidas were kings. [2] Agis was of the Eurypontid royal house, a son of Eudamidas, and the sixth in descent from the Agesilaüs who crossed into Asia and became the most powerful Greek of his time. For Agesilaüs had a son Archidamus, who was slain by the Messapians at Mandurium in Italy¹; Archidamus had an elder son Agis, and a younger son Eudamidas, who, after Agis was slain by Antipater at Megalopolis² leaving no issue, became king; Eudamidas was succeeded by Archidamus, Archidamus by another Eudamidas, and Eudamidas by Agis,³ the subject of this Life. [3] Leonidas, on the other hand, the son of Cleonymus, was of the other royal house, the Agiad, and was eighth in descent from the Pausanias who defeated Mardonius at Plataea. For Pausanias had a son Pleistoanax, and Pleistoanax a son Pausanias, upon whose exile and flight from Sparta to Tegea⁴ his elder son Agesipolis became king; Agesipolis, dying without issue, was succeeded by a younger brother Cleombrotus, [4] and Cleombrotus, in turn, had two sons, Agesipolis and Cleomenes, of whom Agesipolis reigned only a short time and left no sons, while Cleomenes, who became king after him, lived to lose his elder son Acrotatus, but left behind him a younger son Cleonymus Cleonymus, however, did not come to the throne, but Areus,⁵ who was a grandson of Cleomenes and son of Acrotatus; Areus fell in battle at Corinth,⁶ and his son Acrotatus came to the throne; [5] Acrotatus also was defeated and slain at Megalopolis, by the tyrant Aristodemus, leaving his wife with child; and after she had given birth to a son, Leonidas the son of Cleonymus was made the child's guardian. But the young king died before reaching manhood, and the kingship therefore devolved upon Leonidas,⁷ who was altogether unacceptable to the people. [6] For although the destruction of the constitution had already led to a general decline in manners, there was in Leonidas a very marked departure from the traditions of his country, since for a long time he had frequented oriental courts and had been a servile follower of Seleucus, and now sought to transfer the pride and pomp which prevailed abroad into Hellenic relations and a constitutional government, where they were out of place.