Analysis of information sources in references of the Wikipedia article "Các cuộc xâm lược của Mông Cổ" in Vietnamese language version.
In the campaigns waged in western Asia (1253-1258) by Jenghis' grandson Hulagu, "a thousand engineers from China had to get themselves ready to serve the catapults, and to be able to cast inflammable substances." One of Hulagu's principal generals in his successful attack against the caliphate of Baghdad was Chinese.
