What is Dong Qichang's historical position in the Thesis Calligraphy?

Dong Qichang was the master of the Thesis Calligraphy, and the power he injected into the tradition of learning from the masters was unmatched at that time. From Zhong Yao and Er Wang to Zhang Xu, Yan Zhenqing and Huaisu, from Yang Ningshi to the "Four Schools of Song" and even the Yuan's Zhao Mengping, all the postal school calligraphers represented by Er Wang, he took their strengths and weaknesses seriously and drew the essence of them, so as to create his own loom and form his own style of calligraphy which is ancient and light, and vivid and simple.