Editing 1211 (section)

==== Mongol Empire ====
* Spring &ndash; [[Genghis Khan]] summons his Mongol chieftains, and prepares to wage war against the [[Jurchen people|Jurchen]]-led [[Jin dynasty (1115–1234)|Jin dynasty]] in northern [[China]]. He advances across the [[Gobi Desert]] with a massive army of 100,000 warriors with 300,000 horses, strung out in perhaps 10–20 groups of 5,000–10,000 men each, each with camel-drawn carts, and all linked by fast-moving messengers. Meanwhile, the Jin Government mobilizes an army of 800,000 men, most of which are untrained peasants with low morale, and some 150,000 highly-trained cavalry. This vast army, however, is spread across the [[Great Wall of China|Great Wall]], and garrisoned separate fortresses.<ref>Man, John (2011). ''Genghis Khan: Life, death and Resurrection'', p. 164. {{ISBN|978-0-553-81498-9}}.</ref>
* [[Battle of Yehuling]]: Genghis Khan bypasses the Great Wall with little opposition, and splits his forces into two armies. The main army (60,000 men) is led by himself, and the other army is taken by his son [[Ögedei Khan|Ögedei]] to attack the city of [[Datong]]. Genghis heads for the strategic [[Juyong Pass]] ("Young Badger's Mouth") – which leads down to the capital of [[Zhongdu]] (modern-day [[Beijing]]), but along the way he is halted at the pass of Yehuling where the bulk of the Jin army awaits him. Between March and October, the battle is fought in three stages, after Genghis has defeated the Jin forces, he begins raiding the countryside before he withdraws for the winter.<ref>Wolter J. Fabrycky; P. M. Ghare; Paul E. Torgersen (1972). ''Industrial operations research'', p. 313. Prentice-Hall. {{ISBN|978-0-13-464263-5}}.</ref>