It appears evidently from the testimony of Polybius and Plutarch, that the great scheme of the Spartan legislator was, to provide for the lasting security of his country against all foreign invasions, and to perpetuate the blessings of liberty and independency to the people. By the generous plan of discipline which he established, he rendered his countrymen invincible at home. By banishing gold and silver, and prohibiting commerce and the use of shipping, he proposed to confine the Spartans within the limits of their own territories; and by taking away the means, to repress all desires of making conquests upon their neighbours. But the same love of glory and of their country which made them so terrible in the field, quickly produced ambition and a lust of domination; and ambition as naturally opened the way for avarice and corruption. For Polybius truly observes, that as long as they extended their views no farther than the dominion over their neighbouring states, the produce of their own country was sufficient for what supplies they had occasion for in such short excursions.[15] But when, in direct violation of the laws of Lycurgus, they began to undertake more distant expeditions both by sea and land, they quickly felt the want of a publick fund to defray their extraordinary expenses. For they found by experience, that neither their iron money, nor their method of trucking the annual produce of their own lands for such commodities as they wanted (which was the only traffick allowed by the laws of Lycurgus) could possibly answer their demands upon those occasions. Hence their ambition, as the same historian remarks, laid them under the scandalous necessity of paying servile court to the Persian monarchs for pecuniary supplies and subsidies, to impose heavy tributes upon the conquered islands, and to exact money from the other Grecian states, as occasions required.