Chinese general Ban Chao was dispatched to the Western Regions with a small force in 73 CE to pacify the Xiongnu tribes and secure China's control over Central Asia. Over three decades, through military campaigns and diplomacy, he established Han control over 55 states along the Silk Road. In 97 CE, Ban Chao sent envoy Gan Ying westward to establish contact with the Roman Empire, though Gan only reached the Persian Gulf. Ban Chao's campaigns stabilized Silk Road trade routes and extended Han Chinese influence westward.