Why was the Han Dynasty the first golden period of exegetical development?

The Han Dynasty took over the book burning of the Qin Dynasty, many ancient books were destroyed, with the establishment of the Han Dynasty, Emperor Wu of the Han Dynasty, the sole respect for Confucianism, and vigorously advocate the scriptures, the present scriptures, plus the discovery of canonical books such as the "ancient Shangshu", the "ancient Zuozhuan", and the "Rites of the Zhou", etc., which were written in the ancient language (the Warring States tadpole), and so the ancient scriptures in the present scriptures and the rise of the ancient scriptures, it is necessary to study the scriptures to be able to exegetically understand the sound of their meanings, and then the book of exegesis has also Become an important part of the book and the birth of Xu Shen's "Shuowen Jiezi", Yang Xiong's "dialect", Liu Xi's "interpretation of names" and other professional exegesis books.