In the Middle Ages, Hellweg was the official and common name given to main travelling routes in Germany. Their breadth was decreed as an unimpeded passageway a lance's width, about three metres, which the landholders through which the Hellweg passed were required to maintain. From the Early Modern period, with the rise of the coal and steel industries, medieval towns founded along the trading route, e.g. Gelsenkirchen, Bochum, Essen or Dortmund, evolved into industrial hubs and absorbed most of the population growth of the region.