《晋书·志·第四章》
绥服之外五百里为要服，三百里遵常道，二百里减免赋税。
绥服外五百里要服，三百里夷，二百里蔡。
Beyond the sui domain, there was a strip of territory five hundred li in width, which was called the yao domain; within three hundred li, the people conformed to the common rules of conduct; within two hundred li, they were relieved from certain taxes.