"The name [Cathay] first became known to Europe in the 13th century, when the vast conquests of Jenghiz and his house drew a new and vivid attention to Asia. [...]
The conquests of Jenghiz and his successors had spread not only over China and, as it seemed the adjoining East, but westward also over all Northern Asia, Persia, Armenia, part of Asia Minor, and Russia, threatening to deluge Christendom. Though the Mongol wave retired, as it seemed almost by an immediate act of Providence, when Europe lay at its feet, it had levelled or covered all political barriers from the frontier of Poland to the Yellow Sea, and when Western Europe recovered from its alarm, Asia lay open, as never before or since, to the inspection of Christendom. Princes, envoys, priests, - half-missionary half-envoy - visited the court of the great Khan in Mongolia ; and besides these, the accidents of war, commerce, or opportunity carried a variety of persons from various classes of human life into the depths of Asia."
[EDIT : correction to the accreditation of the above article extract thanks to the vigilant sages at www.1902encyclopedia.com]