Zhao Tuo
The court under Lü Zhi was not only unable to deal with a Xiongnu invasion of Longxi Commandery (in modern Gansu) in which 2,000 Han prisoners were taken, but it also provoked a conflict with Zhao Tuo, King of Nanyue, by imposing a ban on exporting iron and other trade items to his southern kingdom. Proclaiming himself Emperor Wu of Nanyue (南越武帝) in 183 BCE, Zhao Tuo attacked the Han Kingdom of Changsha in 181 BCE. He did not rescind his rival imperial title until the Han ambassador Lu Jia again visited Nanyue's court during the reign of Emperor Wen.