[German version]

The modern Indian Ocean (IO) was mostly known to the Greeks as  Erythrá thálatta [1] which actually only referred to the western part. With the increase in geographical knowledge, Erythrá thálatta was also used for the entire ocean (e.g. Peripl. m.r.) that was otherwise called the Indian Sea (Ἰνδικὸν πέλαγος/Indikòn pélagos, Ptol. 7,1,1; 7,2,1) or IO (Ἰνδικὸς ὠκεανός/Indikòs ṓkeanós, Agathemerus 2,4; Oceanus Indicus, Mela 1,9, Sen. Q Nat. 4,2,4). With the large gulfs (Sinus Gangeticus, Sabaracus and Perimulicus) it formed the southern bounda…