Philip Johan von Strahlenberg Volga Samara Bend Obshchy Syrt drainage divide Ural Rivers Ural Mountains Ural Mountains Voltaire Peter the Great Halford Mackinder art continents Ural River Russia Don continent
Four years later, in 1725, Philip Johan von Strahlenberg was the first to depart from the classical Don boundary. He drew a new line along the Volga, following the Volga north until the Samara Bend, along Obshchy Syrt (the drainage divide between the Volga and Ural Rivers), then north and east along the latter waterway to its source in the Ural Mountains. At this point he proposed that mountain ranges could be included as boundaries between continents as alternatives to nearby waterways. Accordingly, he drew the new boundary north along Ural Mountains rather than the nearby and parallel running Ob and Irtysh rivers. This was endorsed by the Russian Empire and introduced the convention that would eventually become commonly accepted. However, this did not come without criticism. Voltaire, writing in 1760 about Peter the Great's efforts to make Russia more European, ignored the whole boundary question with his claim that neither Russia, Scandinavia, northern Germany, nor Poland were fully part of Europe. Since then, many modern analytical geographers like Halford Mackinder have declared that they see little validity in the Ural Mountains as a boundary between continents.
