ancient china was ruled by emperors who keeps order and maintained harmony as china prospered and chinese culture flourished . the nomadic tribes such as the mongols traded horses to their chinese neighbors for things they could not produce themselves such as grain , silk and iron . the great differnces between the two cultures often led to conflict . when the nomads could not get what they wanted by trading they would steal and plunder from the chinese . different emperors throughout the ages had different ways of dealing with the nomads . some tried making peace treaties , some sent soldiers to fight the nomads and some tried to encourage rules and regulation for trading between the two cultures . other emperors bulit walls to keep the nomadic invaders out of china . qin shi huangdi , the first emperor of china , created a unified china by conquering the warring states . in order to defend his new unified country against invading nomads , he built the first long wall in china . more than 800,000 soldiers , peasants and prisoners worked for 10 years to built it . over the years , the wall fell into ruins and other walls were built by other emperors to keep out invaders . in 1449 , the mongols attacked china . the chinese decided to build a wall to keep invaders out . the routes that the mongols used to reach china were blocked with walls . those walls were then connected with other sections of wall , thus creating the great wall of china