What important project did take over after her husband's death as noted in the nonfiction book, The Alexiad of Anna Comnena?

Caesar Nikephoros Bryennios, Anna's husband, was a well-respect general and historian. Caesar initially began writing of a history of Alexius's life and deeds, but when he died, Anna picked up where he let off. She was 55 at the time and wrote the Alexiad which became the major historical source for knowledge about Byzantine history between the 11th and 12th centuries.