Spartan hegemony was clear from 404 to 371. After the battle of Leuctra, not only Sparta lost its hegemony, but also most of Messenia, and the Peloponnesian League, which dissolved. The irruption of Macedonia in the Greek political game hardly helps the situation for it. In 330, King Agis III attacked Antipater, lieutenant of Alexander the Great, at the head of a Peloponnesian coalition, but was defeated and killed at the Battle of Megalopolis. During the Lamiac War, Sparta is too weak to participate. The second burst takes place in -281, under the impulse of King Areus I. Sparta temporarily managed to repel Pyrrhus of Epirus, notably by joining forces with Athens, but in 265 the king was killed and Macedon regained the upper hand.
The weakness of Sparta allows the Achaean League to take off, while a crisis of the Lacedaemonian institutions upsets the city. It is first the revolution of Agis IV, then that of Cleomenes III. The latter tries to stem the advance of the Achaeans, at first with some success, since the League offers him in 226 to take its lead. But an illness prevents him from enjoying this advantage. The war resumed in 225. Again, Cleomenes achieved significant success, but Aratus of Sicyon, who had become a strategist for the League, thwarted the Spartan's plans for conciliation and appealed to the Macedonians, who crossed the Isthmus of Corinth in 224 Weaker financially and militarily, Cleomenes was crushed in Sellasia by Antigone III Doson, king of Macedonia. Sparta is taken and Cleomenes must flee to Egypt.
Significant political unrest ensued in Sparta. In 207, Nabis acceded to the throne - or at least became tyrant of Sparta. Under his reign, the war resumes against the Achaean League. In 205, Sparta becomes the ally of Rome, a fact which modifies the balance of power in the region:Sparta is opposed to the Achaeans, who also become the allies of Rome, which is opposed to Macedonia. All this leads to Philip V of Macedon taking Argos and giving it to Sparta. Nabis made himself popular there by abolishing debts and persecuting the rich.
Rome prefers to let it pass, but from 197, it allies itself with the Greek cities against Sparta. Dominated from all points of view, the city was forced to accept peace in 195. It lost an important part of its territory, the right to recruit in the Periegesis, its port and most of its fleet. /P>
In 192, Nabis was assassinated. Philopoemen, strategist of the Achaean League, obliges Sparta to adhere to it. He becomes the true master of Sparta. He forces the Spartans to tear down their walls, frees the Helots and sends them back on pain of enslaving them as commodity slaves - which happens, in fact, to 3,000 of them. The reforms of Nabis are repealed, the agôgè suppressed. Great confusion ensues in Sparta, between the supporters of the ancient tyrants, the ancient exiles by Nabis, the moderate exiles, etc. The Roman legates, on the other hand, had little influence over the Achaeans. The situation was not settled until 180:all the exiles were recalled, Sparta was able to rebuild its walls and reinstate the agôgè.
But the disagreements with the League do not end there. In 148, the Achaeans attacked Sparta, which was defeated. Rome must intervene, demanding that Sparta and Corinth be separated from Achaia. Furious, the Achaeans take up arms again, but they are crushed by Rome in 146. Sparta is theoretically part of the victorious camp, but in reality, it loses its periec cities, which on their side form the koinon (alliance) of the Lacedaemonians. Sparta is now only a second-rate city, autonomous but isolated, far from its former splendour.