The phrase "Seven Seas" has been used to refer to different bodies of water at various times and places, and there is no definitive answer to this question. The origins of the phrase can be traced back to ancient times, and in various cultures, it has referred to bodies of water along trade routes, regional bodies of water, or exotic and far-away bodies of water. In Greek literature, the Seven Seas were the Aegean, Adriatic, Mediterranean, Black, Red, and Caspian seas, with the Persian Gulf thrown in as a "sea". In Medieval European literature, the phrase referred to the North Sea, Baltic, Atlantic, Mediterranean, Black, Red, and Arabian seas. As trade picked up across the Atlantic, the concept of the Seven Seas changed again, and mariners referred to the Seven Seas as the Arctic, the Atlantic, the Indian, the Pacific, the Mediterranean, the Caribbean, and the Gulf of Mexico. Today, the Seven Seas can refer to the Arctic, North Atlantic, South Atlantic, North Pacific, South Pacific, Indian, and Southern Oceans. However, the ocean is more commonly geographically divided into the Atlantic, Pacific, Indian, Arctic, and Southern (Antarctic) .