In 1931, Josef Karst used linguistic evidence to theorize that there were two Atlantises, one in the Sahara, in North Africa at a time when he theorized that this region was still linked to Sicily via a Sicilian-Tunisian land bridge. The other Atlantis he placed in the Arabian Sea.
The Arabian Sea is a region of the northern Indian Ocean bounded on the north by Pakistan and Iran, on the southwest by northeastern Somalia, on the east by India, and on the west by the Arabian Peninsula. Some of the ancient names of this body of water include Sindhu Sagar (meaning "Sea of river Indus which is also called as Sindhu River" in Sanskrit) and Erythraean Sea.
The Arabian Sea has two important branches — the Gulf of Aden in the southwest, connecting with the Red Sea through the strait of Bab-el-Mandeb; and the Gulf of Oman to the northwest, connecting with the Persian Gulf. There are also the gulfs of Cambay and Kutch on the Indian coast.
The Arabian Sea is seismically active and has a history of forming new islands. In 2013, after a 7.8 magnitude earthquake in Pakistan, three new islands were formed. An island was also formed in the 1950s but soon disappeared.
The Erythraean Sea (Greek: Ἐρυθρὰ Θάλασσα, Erythra Thalassa; "Red Sea") is the name in ancient cartography for a body of water located between the Horn of Africa and the Arabian peninsula. This appellation may have derived from the seasonal blooms of the red-coloured Trichodesmium erythraeum near the water's surface.
In the third century, Flavius Philostratus made this comment: "And they say that the sea called Erythra or "red" is of a deep blue color, but that it was so named, as I said before, from a King Erythras, who gave his own name to the sea in question."
In the opening sentences of Herodotus's history, written in the 5th century BCE, 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.
The Arabian Sea has been an important marine trade route since the era of the coastal sailing vessels from possibly as early as the 3rd millennium BCE, certainly the late 2nd millennium BCE through the later days known as the Age of Sail. By the time of Julius Caesar, several well-established combined land-sea trade routes depended upon water transport through the Sea around the rough inland terrain features to its north.
These routes usually began in the Far East or down river from Madhya Pradesh with transshipment via historic Bharuch (Bharakuccha), traversed past the inhospitable coast of today's Iran then split around Hadhramaut into two streams north into the Gulf of Aden and thence into the Levant, or south into Alexandria via Red Sea ports such as Axum. Each major route involved transhipping to pack animal caravan, travel through desert country and risk of bandits and extortionate tolls by local potentiates.
This southern coastal route past the rough country in the southern Arabian peninsula (Yemen and Oman today) was significant, and the Egyptian Pharaohs built several shallow canals to service the trade, one more or less along the route of today's Suez canal, and another from the Red Sea to the Nile River, both shallow works that were swallowed up by huge sand storms in antiquity. Later the kingdom of Axum arose in Ethiopia to rule a mercantile empire rooted in the trade with Europe via Alexandria.