The next phase of vigorous action on the part of the league is that which corresponds with the career of Philopoemen, who had already shown his energy and skill at the battle of Sellasia. He was elected Hipparch in B.C. 210, and Strategus in B.C. 209. In his first office he did much to reorganise the Achaean cavalry and restore them to some discipline,[128] and he extended this as Strategus to the whole army.[129] His life’s work, however, was the defeating and either killing or confining to their frontier the tyrants of Sparta. But while he was absent from the country after B.C. 200 a new element appeared in the Peloponnese. In 197 the battle of Cynoscephalae put an end for ever to Macedonian influence, and Flamininus proclaimed the liberty of all Greece in B.C. 195 at the Nemean festival. But Nabis was not deposed; he was secured in his power by a treaty with Rome; and when Philopoemen returned from Crete (B.C. 193), he found a fresh war on the point of breaking out owing to intrigues between that tyrant and the Aetolians. They suggested, and he eagerly undertook to make, an attempt to recover the maritime towns of which he had been deprived by the Roman settlement.[130][Sidenote: 193-192.] Nabis at once attacked Gythium: and seemed on the point of taking it and the whole of the coast towns, which would thus have been lost to the league. Philopoemen, now again Strategus (B.C. 192), failed to relieve Gythium; but by a skilful piece of generalship inflicted so severe a defeat on Nabis, as he was returning to Sparta, that he did not venture on further movements beyond Laconia; and shortly afterwards was assassinated by some Aetolians whom he had summoned to his aid. [Sidenote: 189-187.] But the comparative peace in the Peloponnese was again broken in B.C. 189 by the Spartans seizing a maritime town called Las; the object being to relieve themselves of the restraint which shut them from the sea, and the possible attacks of the exiles who had been banished by Nabis, and who were always watching an opportunity to effect their return. Philopoemen (Strategus both 189 and 188 B.C.) led an army to the Laconian frontier in the spring of B.C. 188, and after the execution of eighty Spartans, who had been surrendered on account of the seizure of Las, and of the murder of thirty citizens who were supposed to have Achaean proclivities—Sparta submitted to his demand to raze the fortifications, dismiss the mercenaries, send away the new citizens enrolled by the tyrants, and abolish the Lycurgean laws, accepting the Achaean institutions instead. This was afterwards supplemented by a demand for the restoration of the exiles banished by the tyrants. Such of the new citizens (three thousand) as did not leave the country by the day named were seized and sold as slaves.[131] [Sidenote: B.C. 188.] [Sidenote: 188-183.]