The Chinese have been a very learned and cultured people much before many other people. They started living in cities, trading etc long before their northern neighbours. Most of the north of China was nomadic and tribal. The tribes there relied on herding and hunting and often raided each other and Chinese settlements to procure supplies in times of hardship. These nomads consisted of Mongols, Turkic and Hunnic tribes. They were divided amongst themselves and the Chinese played one against the other from time to time. To keep this threat at bay they built the wall, first from 220 BC to 200 BC under the Qin dynasty. The first wall was merely of mud, but later constructions were much better built of stone and contained barracks and stone towers as fell. When the Mongols did finally unite under one leader, Genghis Khan, the wall was no match as in some parts it was in a state of disrepair. The Mongols just rode around the better part of the fortification and opened the gates of their destiny.