Question: who was involved in the great wall of china

title: History of the Great Wall of China
text: In the 13th century , the Mongol leader Genghis Khan , once a vassal of the Jurchens , rose up against the Jin dynasty . In the ensuing Mongol conquest of the Jin dynasty , the nomadic invaders avoided direct attacks on the Jin fortifications . Instead , when they could , the Mongols simply rode around the walls ; an effective example of this tactic is in 1211 , when they circumvented the substantial fortress in Zhangjiakou and inflicted a terrible defeat upon the Jin armies at the Battle of Yehuling . The Mongols also took advantage of lingering Liao resentment against the Jin ; the Khitan defenders of the garrisons along the Jin walls , such as those in Gubeikou , often preferred to surrender to the Mongols rather than fight them . The only major engagement of note along the main Great Wall line was at the heavily defended Juyong Pass : instead of laying siege , the Mongol general Jebe lured the defenders out into an ambush and charged in through the opened gates . In 1215 , Genghis Khan besieged , captured , and sacked the Jin capital of Yanjing ( modern - day Beijing ) . The Jin dynasty eventually collapsed following the siege of Caizhou in 1234 . Western Xia had already fallen in 1227 , and the Southern Song resisted the Mongols until 1279 .