In the Lower Status, the higher attributes of mankind begin to develop: personal dignity, eloquence, religious sensibility, rectitude, manliness and courage, now common traits of character; but there was also cruelty, treachery and fanaticism. Element worship in religion, with a dim conception of personal gods, and of a Great Spirit, rude verse-making, joint tenement houses, and bread from maize belong to this period. It produced also syndiasmian family and confederacy of tribes, organised into phratries and gentes. The imagination, that great faculty so largely contributing to the elevation of mankind, was now producing an unwritten literature of myths, legends and traditions, already become a powerful stimulus upon the race. Danaus and AEgyptus were brothers and descendants of the Argive Io. Danaus had fifty daughters by different wives and AEgyptus fifty sons; the latter sought the first in marriage; these, according to the Turanian system, were brothers and sisters, and so not intermarriable. If there had been descent in male line, they would also have belonged to the same gens, and this would have been another obstacle to marriage. The fifty daughters of Danaus the Danaides fled from Egypt to Argos to escape unlawful and incestuous wedlock. This event was foretold to Io by Prometheus Aeschylus, 853). In AEschylus play The Supplices the Danaides declare to the kindred Argives (in Argos) that they had not been exiled from Egypt (The passage seems spoiled, grammatically; see Sch tz, AEschylus (Vol. 2, p. 378). Further: After they heard the case of the suppliants, the Argives decided in council to grant them protection, which implies the existence of a ban on such marriages and the validity of their objection. At the time this tragedy was performed, in Athens, Athenian law itself facilitated and promoted marriage between children of brothers in the case of heiresses and orphans, although this rule seems to have been confined to such exceptional cases.
Conspectus of Lewis Morgan's Ancient Society, Marx