evidence: Crossed by the Northern Silk Road,[56] the Tarim and Dzungaria regions were known as the Western Regions. At the beginning of the Han dynasty the region was ruled by the Xiongnu, a powerful nomadic people.[57]: 148 During the 2nd century BC, the Han dynasty prepared for war against Xiongnu when Emperor Wu of Han dispatched Zhang Qian to explore the mysterious kingdoms to the west and form an alliance with the Yuezhi against the Xiongnu. As a result of the war, the Chinese controlled the strategic region from the Ordos and Gansu corridor to Lop Nor. They separated the Xiongnu from the Qiang people on the south and gained direct access to the Western Regions. Han China sent Zhang Qian as an envoy to the states of the region, beginning several decades of struggle between the Xiongnu and Han China in which China eventually prevailed. During the 100s BCE, the Silk Road brought increasing Chinese economic and cultural influence to the region.[57]: 148 In 60 BCE, Han China established the Protectorate of the Western Regions (西域都護府) at Wulei (烏壘, near modern Luntai), to oversee the region as far west as the Pamir Mountains.