Confucius not only "modeled upon Kings Wen and Wu of the Zhou" but also "transmitted the ancient traditions of Yao and Shun". His motive behind the former was to rebuild social norms by selectively inheriting the systems of Rites and Music of the Zhou. This was Confucius' life-long devotion and aspiration. Through "transmitting the ancient traditions of Yao and Shun," he aimed to continue the way of the "mean". This was a sublimation of his thought, which took place after his age of "understanding heaven's mandate" (i.e., fifty years of age). The way of the "mean" is a central theme that goes through the classics and their respective commentaries. Yao transmitted it to Shun, Shun to Yu, Yu to Chengtang, and Chengtang to Kings Wen and Wu, who passed it down to Confucius. The way of the "mean" links up the entirety of Confucius' thought. This long, enduring genealogy forms the "tradition of the Way", which symbolizes the continuous Chinese civilization that was derived from one common source. It represents Chinese national historical identification. In his old age, Confucius compiled and wrote the Book of Documents and Annals of the Spring and Autumn Period. The format and content of these works reveals his cultural consciousness of inheriting the "tradition of the Way".