The sacredness of the horse to Poseidon, the epithets Hippios and Equester applied to Poseidon and Neptune, the Greek fable of the origin of the first horse (produced by Poseidon striking the ground with his trident), and the custom in Argolis of sacrificing horses to Poseidon by drowning them in a well.
In Laconia Aristodemus (or his twin sons) effected a rigid military occupation which eventually embraced the whole district, and permitted (a) the colonization of Melos, Thera and parts of Crete (before 800 B.C.), (b) the reconquest and annexation of Messenia (about 750 B.C.), (c) a settlement of half-breed Spartans at Tarentum in south Italy, 700 B.C. In Argos and other cities of Argolis the descendants of the Achaean chiefs were taken into political partnership, but a tradition of race-feud lasted till historic times.
Many of the colonists, however, were not Ionians, but refugees from other parts of Greece, between Euboea and Argolis (Hdt.
In Argolis Proetus built Tiryns, but later, under Perseus, Mycenae took the lead until the Achaean conquest.
At the fountain of Dine in Argolis horses bitted and bridled were sacrificed to him by being drowned (Pausanias viii.
Most non-Dorian Greeks, in fact, seem to have accepted much as Dorian which was in fact only Spartan: this was particularly the case in the political, ethical and aesthetic controversies of the 5th and 4th centuries B.C. Much, however, which was common (in art, for example) to Olympia, Argolis and Aegina, and might thus have been regarded as Dorian, was conspicuously absent from the culture of Sparta.