During the reign of the Qing emperor Kangxi (1662–1722), Jesuit missionaries introduced European techniques of glassmaking and apparently of reverse painting on glass in China. Chinese craftsmen excelled to such a degree, that Chinese reverse paintings on glass often are misidentified as being French or English. According to a contemporary source, most Chinese glass painters worked in Canton, which at the same time was the center of the trade with Europe. Miniature portraits, often executed in lacquer on copper, were very popular during the late 18th century, and the glass medallions with two European ladies follow this fashion. The portraits are very delicate. They might have been executed after watercolor or pastel portraits, but it is possible they depict ladies who actually stayed in China.