In 1904, the University Constitution stipulated that the subject of "Advanced Calculation" be part of the science department and listed the required and supplementary courses of "Calculation Subject". In the fall of 1913, Peking University began enrolling math students, proclaiming the beginning of teaching activities of advanced mathematics in China. In 1919, the Department of Mathematics was listed as, and has been ever since, the first department among all departments. President Cai Yuanpei issued a statement for his decision. "The mission of all universities is that those engaged in the philosophy, literature and applied sciences, shall start with pure sciences; those engaged in pure sciences, shall start with mathematics. Therefore, the mathematics department shall be listed as the first among all departments." During the World War II, the Department of Mathematics of Peking University, relocated in the city of Kunming of Yunnan Province, operated jointly with the counterpart of Tsinghua University and Nankai University for 8 years. In 1952, the three mathematics departments at Peking University, Tsinghua University, and Yenching University were merged to form the new Department of Mathematics and Mechanics at Peking University，after the counterpart of the Moscow State University. The division of Mechanics later evolved into an independent department in 1978. So did the division of Probability and Statistics in 1985.