In 648, the Book of Jin, the official history of Jin dynasty, with Fang as its lead editor, was completed. Also in 648, when Emperor Taizong was at another summer palace, Yuhua Palace (玉華宮, in modern Tongchuan, Shaanxi), he again left Fang in charge of Chang'an, when Fang grew ill. Emperor Taizong summoned him to Yuhua Palace and had the imperial servants attend to him.
The Book of Jin, the official history of the Jin dynasty, was completed in 648 under the guidance of Fang as its chief editor. Furthermore, when Emperor Taizong was at his summer retreat, Yuhua Palace, he once again delegated authority over Chang'an to Fang, but only because Fang was unwell. Upon being informed of Fang's condition, Emperor Taizong sent for him and ordered the imperial attendants to tend to his needs.