section_path: History/Medieval era
section_name: Medieval era
paragraph_text: Medieval era
  
  The Islamic Caliphate 's defeats of the Byzantine and Persian empires led to West Asia and southern parts of Central Asia and western parts of South Asia under its control during its conquests of the 7th century; Islam also spread over centuries to the southern regions of India and Southeast Asia through trade along the Maritime Silk Road. The Mongol Empire conquered a large part of Asia in the 13th century, an area extending from China to Europe. Before the Mongol invasion, Song dynasty reportedly had approximately 120 million citizens; the 1300 census which followed the invasion reported roughly 60 million people.
  
  The Black Death, one of the most devastating pandemics in human history, is thought to have originated in the arid plains of central Asia, where it then travelled along the Silk Road.