The Greeks themselves derived the name from an eponymous King Erythras and knew that the waters so described were deep blue.[2][3] Modern scholars sometimes attribute the name to the seasonal blooms of the red-hued Trichodesmium erythraeum in the Red Sea.[4]Agatharchides had written of the origin of the name Erythraean Sea on the book (De Mari Erythraeo, § 5) in a story about the king Erythras: "There was a man famous for his valor and wealth, by name Erythras, a Persian by birth, son of Myozaeus.... the glory of the Island ascribed to him by the popular voice because of these his deeds, that even down to our own time they have called that sea, infinite in extent, Erythraean Sea".[5]
The name "Erythraean Sea" has been or is still used for the following places:
In the opening sentences of Herodotus' history, written in the 5th century BC, he refers to the Phoenicians having come originally from the Erythraean Sea.
In the Periplus of the Erythraean Sea, written in the 1st century AD, as well as in some ancient maps, the name of the sea refers to the whole area of the northwestern Indian Ocean, including the Arabian Sea.[6]
In centuries past, the name "Erythraean Sea" was applied by cartographers to the north-western part of the Indian Ocean, mainly the area around Socotra, between Cape Guardafui and the coast of Hadhramaut. This appellation has now become obsolete and the name Gulf of Aden is used although for a smaller area. In maps in which the north-western part of the Indian Ocean is named thus, the Red Sea appears as "Arabian Gulf".
The name "Erythraean Sea" was used as well to refer to some gulfs attached to the Indian Ocean, specifically, Gulf of Aden and Gulf of Oman.[7]
As a name for the Red Sea, especially after the 19th century. The modern country of Eritrea was named after the Ancient Greek name.
Since 1895, the name has also been applied to a large dusky region on the surface of planet Mars that is known as Mare Erythraeum.
Josephus, Berossus from Alexander Polyhistor, Of the Cosmogony and Causes of the Deluge (The Ancient Fragments trans. Cory 1828 p. 19) (Romano-Jewish-Babylonian history C1st AD)
Plutarch, Moralia, Bravery of Women, 3 (The Women of Chios) 244F ff (trans. Babbitt) (Greek history C1st to C2nd AD)
Plutarch, Moralia, Bravery of Women 17 (Polycrite) 254C ff
Plutarch, Moralia, The Greek Questions (30) 298B ff
The Periplus of the Erythrean sea, containing an account of the navigation of the ancients, from the sea of Suez to the coast of Zanguebar, William Vincent (ed.), 2 voll., London, 1800, vol. 1, vol. 2.