Toward the end of the 13th century, while a guest in the court of Kublai Khan, Marco Polo was stunned by the beautiful grassland enclosed in the imperial palace, which teemed with fruit trees and breeding animals such as deer and goats.
Roughly 300 years later, Beijing had become a crowded, windswept city; the Jesuit missionary Matteo Ricci often wore a veil when he went out, partly to move around undisturbed and partly to keep out the dust. In the late 17th century, two Jesuits, Jean-Francois Gerbillon and Joachim Bouvet, were brought to the palace to teach the principles of Euclidean geometry to the Kangxi Emperor, who made time for four hours of daily lessons in between his other duties.
