Why were Tsinghua students called "classmates of the Emperor of the Qing Dynasty, disciples of the Saints of the South China Sea"?

Now Tsinghua University is a famous engineering school, many people do not know that tsinghua liberal arts in the Republic of China period is equally strong, especially the Institute of Chinese Studies of Tsinghua University, founded in 1925, is even more famous.

In 1929, the Institute of Chinese Studies has trained more than 70 graduates in just four years, and fifty of them have become famous scholars in the field of literature and history, and the results are very great.

The tutors of the institute are wang Guowei, Chen Yinke, Liang Qichao, Zhao Yuanren and other first-class scholars.

Once, when Mr. Chen Yinke was in class, he wrote a couplet to the students of the National College, saying that they were "the classmates of the Emperor of the Great Qing Dynasty, and the saints of the South China Sea re-passed on their disciples."

What does this mean?

It turned out that Mr. Wang Guowei, the tutor of the National Academy, had once served as an imperial teacher and taught Puyi's studies, so the students who came to the National College had the same friendship with Puyi, so they were called classmates of Puyi, the emperor of the Qing Dynasty.

Nanhai sage is Kang Youwei, he is a native of Nanhai County, Guangdong, ancient customs to use the place of origin to refer to people, such as Li Hongzhang also known as Li Hefei, another mentor Liang Qichao is his disciple, so the students of Tsinghua Guo college are considered to be kang Youwei students, so they are called Nanhai sage re-disciple.