section_path: Definition and boundaries/Asia–Europe boundary
section_name: Asia–Europe boundary
paragraph_text: Asia–Europe boundary
  
  The threefold division of the Old World into Africa, Asia, and Europe has been in use since the 6th century BCE, due to Greek geographers such as Anaximander and Hecataeus. Anaximander placed the boundary between Asia and Europe along the Phasis River (the modern Rioni river) in Georgia of Caucasus (from its mouth by Poti on the Black Sea coast, through the Surami Pass and along the Kura River to the Caspian Sea), a convention still followed by Herodotus in the 5th century BCE. During the Hellenistic period, this convention was revised, and the boundary between Europe and Asia was now considered to be the Tanais (the modern Don River). This is the convention used by Roman era authors such as Posidonius, Strabo and Ptolemy.
  
  The border between Asia and Europe was historically defined by European academics.
  
  In Sweden, five years after Peter's death, in 1730 Philip Johan von Strahlenberg published a new atlas proposing the Ural Mountains as the border of Asia. Tatishchev announced that he had proposed the idea to von Strahlenberg. The latter had suggested the Emba River as the lower boundary. Over the next century various proposals were made until the Ural River prevailed in the mid-19th century. The border had been moved perforce from the Black Sea to the Caspian Sea into which the Ural River projects. The border between the Black Sea and the Caspian is usually placed along the crest of the Caucasus Mountains, although it is sometimes placed further north.