Pirates and their sailing ships are inexorably linked to the romantic concept of the seven seas, and some variation of the phrase “sailing the seven seas” has existed since ancient mariners plied the Mediterranean Sea and the waters of the Middle East. But which bodies of water are those seven?
A definitive list of the bodies of water that made up the seven seas varied from one culture to another and changed over time. To complicate matters, seven was likely not literal, but rather it was probably used by some cultures as a stand-in for the word many. (The significance of the number seven may be related to its status during biblical times as a symbolic number to exemplify both good things and bad things. There are seven deadly sins and seven days in a week.) For some, the seven seas were simply parts of trade routes. For others, the seven seas were familiar bays, gulfs, seas, and stretches of ocean. In yet other cases, the term had the effect of inspiring a spirit of adventure by referring to waterways that were both strange and distant. “Sailing the seven seas” meant one thing to people living in the Middle East and another to people living in Europe or eastern Asia. Moreover, sometimes the “seas” weren’t even true seas. As a result, there was no true universal understanding of what the seven seas were.
Fortunately, various cultures kept fairly decent records on this topic. The seven seas of the Persians were composed of a handful of major rivers of Central Asia and their tributaries, whereas those of the ancient Arabs spanned the coastal waterways that connected the lands bordering the Persian Gulf to those of the South China Sea. According to the National Oceanic and Atmospheric Administration’s National Ocean Service, the seven seas of the ancient Greeks were the Aegean, the Adriatic, the Mediterranean, the Black, the Red, and the Caspian seas and the Persian Gulf. However, other sources might have swapped in the Indian Ocean for the Aegean Sea. Possibly as a reflection of the growth of knowledge, the seven seas of medieval Europeans shifted to include the Atlantic Ocean and the Arabian, the Baltic, the Black, the Mediterranean, the North, and the Red seas. During the period of European exploration, the list of seven seas changed again, this time using the four traditional oceans (the Atlantic, the Pacific, the Indian, and the Arctic) as the list’s backbone, along with the Mediterranean and the Caribbean seas and the Gulf of Mexico.
Between the 19th century and today, the seven seas could have been renamed the seven oceans, since no seas make the list anymore. Yet, doing so would risk the loss of this familiar romantic alliteration. The four traditional oceans are represented here, of course, and the division of the Atlantic and Pacific into their northern and southern basins brings the tally to six. The seventh body of water on the list is the Antarctic Ocean (Southern Ocean), a region of cold water that surrounds the continent of Antarctica, which is often considered separate from the Atlantic, Pacific, and Indian oceans by the presence of a barrier of powerful winds and turbulent seas.