Through the immigration of the Heracleids, Peloponnesus acquired a new form: the countries and their inhabitants became changed; in Arcadia alone the ancient population remained the same; all other parts received either new inhabitants or new rulers. During that period there arose the three great Doric kingdoms of Messene, Sparta, and Argos, and the Aetolian kingdom of Elis; and Aegialea, which had been an Ionian country, became Achaean. This state of things remains the foundation of geography till after the Macedonian period, when it became completely changed; but although the principal divisions remained until that period, yet their boundaries underwent considerable modifications, which will be explained in the account of each particular country. The three Doric kingdoms in particular did not preserve the same boundaries, for Messene perished, and was united with Laconia; Argolis had originally a much greater extent in the south, but afterwards its frontier in that direction was narrowed, while, on the other side, the three or four cities on the Acte, as well as Corinth, Phlius, and Sicyon, also became separated from it. In this manner Argos, the greatest of those three kingdoms, extending from Malea to Sicyon, and containing one-third of all Peloponnesus, was greatly reduced. Afterwards Messene again rose from its ruins, Argos extended its frontier towards Sparta, Arcadia regained what it had lost, though the towns remained separate, and the boundaries of Achaia were again widened, until its name extended over all Peloponnesus. ARGOLIS, ARGOS. Argos, as I said before, was originally the largest of the three Doric states. The fact that Lacedaemon afterwards appears as the first state of Peloponnesus, is only owing to the good fortune and the pride of the Lacedaemonians, and to the circumstance that they retained their royal dynasty, while the others, especially Argos, lost theirs, in consequence of which the unity of their state was broken. But Argos never recognised the pretensions of Sparta, and this struggling against what was an actual fact, did great harm to Argos, and led it to form most hateful alliances against the rest of the Greeks.