Before revision: In the same period, European explorers of the Silk road like William Rubruck and Marco Polo increase geographical knowledge of Asia in the west, in particular establishing that the Caspian Sea is not connected to the northern ocean.
After revision: In the same period, European explorers of the Silk Road like William Rubruck and Marco Polo increase geographical knowledge of Asia in the west, in particular establishing that the Caspian Sea is not connected to the northern ocean.