Ban Zhao is the foremost female historian of China. Her father, a famous historian, set out to write the Book of Han, the most comprehensive history of that period. He died before he could finish it. Ban Zhao took up where he left off, and after many years of research and writing, completed the work. It was compiled into forty volumes, and was a monumental literary and historical achievement. The emperor was so impressed with her erudition and wisdom that he invited her to live in the palace. She became the teacher to his wives and children.