The phrase “the seven seas” is an ancient, idiomatic expression symbolizing the entirety of the world’s navigable waters rather than a fixed geographic classification. The identity of these seven bodies of water has changed dramatically throughout history, depending on the civilization using the term. The concept is rooted in the significance of the number seven in many ancient cultures, resulting in multiple, distinct historical lists that reflect the known maritime geography of their time.
The Classical European Interpretation
The interpretation most commonly associated with Western medieval literature and exploration centers on regional bodies of water known to ancient European and Near Eastern traders. This list served as a practical description of the waters a merchant or sailor would traverse on major routes. The specific names included the Mediterranean Sea, which was the central hub for ancient commerce and civilization.
The list typically featured the Adriatic Sea and the Black Sea, which extended trade networks north from the Mediterranean. Moving east, it included the Red Sea and the Persian Gulf, providing access to the trade of the Arabian Peninsula and points farther east. Rounding out this regional group were the landlocked Caspian Sea and the Arabian Sea, an arm of the greater Indian Ocean. This compilation of seven separate bodies of water represented the known world’s limits for many European sailors before the Age of Discovery.
Historical Definitions Beyond Europe
The idea of a fixed number of major seas was not exclusive to Europe; other influential cultures developed their own lists based on their trade routes. For example, the Arabs, who dominated maritime trade between the Middle East and Asia, had a different set of seven seas. These were defined by the successive bodies of water a merchant would cross on a voyage to China.
This Arabian or Persian list focused on the eastern trade routes and included the Persian Gulf, the Arabian Sea, and the Bay of Bengal. Further east, the list continued with the waters of Southeast Asia:
- The Strait of Malacca
- The Singapore Strait
- The Gulf of Thailand
- The South China Sea
This demonstrates that the term was a flexible descriptor, signifying a long journey across the known navigable waters in a particular region.
Modern Context and the World’s Major Oceans
Today, the phrase “sailing the seven seas” is used almost entirely as a metaphorical expression to denote an experienced sailor who has traveled everywhere. Modern geography does not recognize a list of seven seas; instead, it uses a standard model of five major global oceans. These five oceans are vast, contiguous bodies of water that collectively form the single, continuous World Ocean.
The five recognized oceans are the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, the Arctic Ocean, and the Southern Ocean. The Southern Ocean, also known as the Antarctic Ocean, was officially recognized by the International Hydrographic Organization in 2000, formalizing the current five-ocean standard. This modern scientific division replaces the historical lists of smaller, regional seas, which are now classified as marginal seas or gulfs of the greater oceans. The historical lists, though culturally significant, are no longer relevant for contemporary oceanography or cartography.