《后汉书·列传·苏竟杨厚列传上》
光武即位，就拜他为代郡太守，让他强固边塞以拒匈奴。
光武即位，就拜代郡太守，使固塞以拒匈奴。
After Emperor Guangwu came to the throne, Su was promoted to be the Prefect of Daijun, to be in charge of strengthening border defense to resist Huns.