请帮忙标准翻译下，谢谢

公元15世纪，我国著名航海家郑和从南京出发下西洋，使这座城市与世界很多国家建立了联系，从而开启了南京对外交往的历史篇章。 In the 15th century, the seven overseas voyages, which were launched from Nanjing by renowned Chinese master mariner, prompted the city to establish ties with many foreign countries, th