In 135 BC, the Han envoy Tang Meng brought gifts to Duotong, the king of Yelang, which bordered Dian, and convinced him to submit to the Han. The Jianwei Commandery was established in the region. In 122 BC, Emperor Wu dispatched four groups of envoys to the southwest in search of a route to Daxia in Central Asia. One group was welcomed by the king of Dian but none of them were able to make it any further as they were blocked in the north by the Sui and Kunming tribes of the Erhai region and in the south by the Di and Zuo tribes. However they learned that further west there was a kingdom called Dianyue where the people rode elephants and traded with the merchants from Shu in secret.