The Xiong Noo was a nation of nomadic herdsmen who shared the same ancestry as the neighbouring Chinese, but separated from them in 1800 B.C. They became a major threat from 700BC, when China entered a time of conflict between rival warlords. The Xiong Noo took advantage of the situation and crossed the borders into the Northern provinces, particularly during harvest time, looting, killing and kidnapping. The Chinese built walls in an attempt to defend themselves. These were eventually fortified and linked together to create the Great Wall of China, but even this structure could not protect them entirely. They launched many military campaigns deep into the Gobi desert in an effort to defeat their old adversary. In 99 B.C. an army of Chinese infantry, five thousand strong met the Xiong Noo cavalry of one hundred thousand. This was, arguably the most heroic battle in China's history.