Born into a long line of soldiers, Qi Jiguang became a commander of his local Garrison at just 17. By 22 he headed off to Beijing to take part in the Imperial Exam when Mongol troops lead by Altan Khan invaded the capital. Seeing his chance to impress, Jiguang took part in defence and helped see the defeat of the invaders. Three years later he was promoted to "Assistant Regional Military Commissioner" and sent to deal with the Wokou Pirates that raided the South coast. Upon arrival, Jiguang discovered that the "soldiers" he was assigned to were really just farmers and miners who volunteered. Nevertheless, Jiguang set about creating a manual that would teach anybody how to become a soldier, and so his book "Jixiao Xinshu" (New Treatise on Military Efficiency) was created. By the time he returned to Beijing 15 years later, Jiguang was now in command of an army of 10,000 elite soldiers and defeated the pirates time after time. He was eventually re-assigned to deal with the Mongol threating to overthrow Beijing. He came up with the idea to rebuild the old Qin Dynasty's Great Wall with brick and mortar and construct hollow watchtowers along it, allowing soldiers interior space to live, store food and water, stockpile weapons, and take shelter from Mongol arrows. The plan was successful and the Mongol threat had dramatically decreased, however this new peace meant that Jiguang's enemies in the Imperial Court were able to challenge his position due to the huge cost of the Wall and were able to slowly get rid of any political allies. Eventually they were able to convince the new Emperor that Jiguang had grown too powerful and posed a threat of a potential coup d'état and so the Emperor forcibly relieved Jiguang of his post and retired him to an idle post in the far south of China. Nevertheless, he was still remembered as a brilliant general and his books on strategy were invaluable to the military leaders that succeeded him.