The Erythraean Sea (Greek: Ἐρυθρὰ Θάλασσα, Erythrà Thálassa, lit. "Red Sea") was a former maritime designation that always included the Gulf of Aden and at times other seas between Arabia Felix and the Horn of Africa. Originally an ancient Greek geography, it was used throughout Europe until the 18-19th century. At times the name frequently extended beyond the Gulf of Aden—as in the famous 1st-century Periplus of the Erythraean Sea—to include the present-day Red Sea, Persian Gulf, and Indian Ocean as a single maritime area.