For who is not aware that they were almost the first of the Greeks to cast longing eyes on the territory of their neighbours, making war on the Messenians out of covetousness and for the purpose of enslaving them?
And is it not narrated by all historians how out of sheer obstinacy they bound themselves by an oath not to desist from the siege before they had taken Messene?
It is no less universally known that owing to their desire of domination in Greece they were obliged to execute the behests of the very people they had conquered in battle.
For they conquered the Persians when they invaded Greece, fighting for her freedom;
but when the invaders had withdrawn and fled they betrayed the Greek cities to them by the peace of Antalcidas, in order to procure money for establishing their sovereignty over the Greeks;
and here a conspicuous defect in their constitution revealed itself.
For as long as they aspired to rule over their neighbours or over the Peloponnesians alone, they found the supplies and resources furnished by <a class="linkToPlace" target="_blank" href="/place?placename=Laconia&groupId=662&placeId=1211">Laconia</a> itself adequate, as they had all they required ready to hand, and quickly returned home whether by land or sea.
But once they began to undertake naval expeditions and to make military campaigns outside the <a class="linkToPlace" target="_blank" href="/place?placename=Peloponnese&groupId=861&placeId=1552">Peloponnese</a>, it was evident that neither their iron currency nor the exchange of their crops for commodities which they lacked, as permitted by the legislation of Lycurgus, would suffice for their needs,
since these enterprises demanded a currency in universal circulation and supplies drawn from abroad;
and so they were compelled to be beggars from the Persians, to impose tribute on the islanders, and exact contributions from all the Greeks, as they recognized that under the legislation of Lycurgus it was impossible to aspire, I will not say to supremacy in Greece, but to any position of influence.
Walbank Commentary