Continuing the Book of Han
Ban Zhao’s father Ban Biao and brother Ban Gu spent decades of effort compiling the Book of Han, and when Ban Gu died in prison for involvement in a political case the history still had many unfinished chapters; Emperor He of Han specially summoned Ban Zhao to the palace and commanded her to continue and complete the "Eight Tables" and "Treatise on Astronomy" from the materials her brother had left — this annals-biography dynastic history thereafter became one of the most complete in form of the "Twenty-Four Histories."