Prince of the Ethiopians, who went to the assistance of his uncle Priam, and was slain by Achilles. His mother Eos was inconsolable for his death, and wept for him every morning.
The Greeks used to call the statute of Am enophis III., in Thebes, that of Memnon. This image, when first struck by the rays of the rising sun, is said to have produced a sound like the snapping asunder of a chord. Poetically, when Eos (morning) kisses her son at daybreak, the hero acknowledges the salutation with a musical murmur. The word is the Egyptian mei-amun, beloved of Ammon.
“Memnon bending o'er his broken lyre.”
Black, but such as in esteem Prince Memnon's sister might beseem.
The legend given by Dictys Cretensis (book vi.) is that Himera, on hearing of her brother's death, set out to secure his remains, and encountered at Paphos a troop laden with booty, and carrying Memnon's ashes in an urn. Pallas, the leader of the troop, offered to give her either the urn or the booty, and she chose the urn.
Probably all that is meant is this: Black so delicate and beautiful that it might beseem a sister of Memnon the son of Aurora or the early day-dawn.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894