Mongol conquest of Western Xia
For nearly a decade the Western Xia served the Mongols as vassals and aided them in the Mongol–Jin War , but when Genghis invaded the Islamic Khwarazmian dynasty in 1219 , Western Xia attempted to break away from the Empire and ally with the Jin and Song dynasties . 
<triplet> Mongol–Jin War <subj> Song dynasties <obj> participant <triplet> invaded <subj> 1219 <obj> point in time