Ban Gu created this kind of chapter in the
汉书, and most later official histories kept it, so a reader also meets the Treatise on Penal Law of the
晋书, the
旧唐书 or the History of Yuan. The Han treatise tells how in 167 BC a girl named
缇萦 offered to become a government slave to save her father from mutilation, and how her letter moved Emperor Wen to abolish such punishments.
