The rise of Islam and Muslim conquests in the 7th century established a sharp opposition, or even a sense of polarity, between medieval European Christendom and the medieval Islamic world (which stretched from the Middle East and Central Asia to North Africa and Andalusia). Popular medieval European knowledge of cultures farther to the East was poor, dependent on the wildly fictionalised travels of Sir John Mandeville and legends of Prester John, although the equally famous, and much longer, account by Marco Polo were more accurate.