Lei Hai-tsung (1902-25 December 1962), historian known for his cyclic theory of Chinese history and his studies of ancient Chinese culture. He taught at Tsinghua University from 1932 until 1952, when the Central People's Government transferred him to Nankai University. Although he remained at Nankai until his death, after 1957 he was forbidden to teach Chinese history because of his outspoken criticism of the Communists during the Hundred Flowers campaign.

The eldest of five brothers. Lei Hai-tsung was born into a scholarly Christian family in the Yungch'ing district of Chihli (Hopei). A number of his forebears had been prominent residents of T'ungchou (near Peking), but his father. Lei Ming-hsia, an Anglican priest, had been assigned to Ta-wang-chuang, outside the walled city of Yungch'ing, sometime before Lei Hai-tsung was born. His father became an intimate friend of and lived with Chu Chiu-tan, a leading local scholar, bibliophile, and connoisseur. It was in the Chu household that Lei Hai-tsung received his early training in Chinese classics. Lei received his formal education first at the Ts'unshih School in Yungch'ing and then at the Ch'ungte Middle School in Peking, both of which were Anglican mission schools. In 1919 he enrolled at Tsinghua Junior College, from which he was graduated in 1922. He then went to the United States, where he completed his undergraduate work at the University of Chicago in 1924. He received a Ph.D. from the same institution in 1927 after writing a dissertation entitled "The Political Ideas of Turgot" and studying under the eminent medievalist James Westfall Thompson.

After returning to China in 1927, Lei Haitsung became a professor of history at National Central University in Nanking. In 1931 he joined the faculty of Wuhan University and published the results of his investigation of the Chou conquest of Shang, fixing its date as 1027 B.C. His conclusions were supported by the later inquiries of William Hung (Hung Yeh) at Yenching University and of the Swedish scholar Bernhard Karlgren. In 1932 T. F. Tsiang (Chiang T'ing-fu, q.v.) persuaded Lei to join the history department of Tsinghua University. At this point, Lei turned away from European history and devoted himself to developing a general theory of Chinese history and to studying ancient Chinese history. For use in teaching, he compiled and edited a six-volume source book of Chinese history, Chung-kuo t'ung-shih hsuan-tu, which was privately printed at Tsinghua. Between 1932 and 1937 he published important articles in the Ch'ing-hua hsueh-pao [Tsinghua journal] and the She-hui k'e-hsueh [the social sciences] on such subjects as the periodicity of Chinese history, the rules and practices of imperial succession in pre-modern empires, the evolution of the Chinese family and kinship system from ancient to medieval times, and the evolution of the Chinese army in terms of social composition and morale. These studies were revised and published in 1940 as Chungkuo wen-huayü Chung-kuo ti ping [Chinese culture and the Chinese soldier].

The core of Lei's approach to Chinese history was his theory of periodicity. Using philosophy and religion as his main criteria, he divided Chinese history into two long cycles, each within five stages. The stages of the first cycle (c.1300 B.C.-383 A.D.) were: (1) the period of Sinitic religion based on ancestor worship (c. 1300-771 B.C.); (2) the rise of creative philosophy to its culmination in the thought of Confucius (770-473 B.C.), a period also characterized by the decline of the royal house of Chou, the emergence of feudal hegemonies and a balance of power among them, and the gradual disintegration of feudal social order; (3) the decline of creative philosophy into sectarianism (473-221 B.C.), accompanied by the transformation to "unitary" states, the passing of chivalry, the emancipation of serfs, the development of a universally conscripted army, and a prolonged internecine military struggle; (4) the period of merger and stagnation of thought (221 B.C.-88 A.D.); and (5) the period of cultural disintegration (89-383 A.D.), which coincided with political disintegration, barbarian conquest of north China, and the introduction of Buddhism. The second cycle in the history of China comprised: (1) the period of Buddhist domination of Chinese life and thought (383-960) ; (2) the rise of Neo- Confucianism (960-1279); (3) the decline of Neo-Confucianism into sectarian conflict (12791518); (4) the death of creative philosophy, leading to the rise of textual and historical criticism (1528-1839); and (5) the disintegration of traditional culture and institutions and the widespread introduction of Western thought and culture (1839-), a period similar to the final stage of the first cycle.

Lei's studies of the changing social composition and quality of the traditional Chinese army also had a bearing on his cyclical theory. In his opinion, much of the dynamism of the period of Warring States and the early empires was accounted for by the development of a conscripted army of free commoners. After the decline of this form of universal military service in the Later Han period, the Chinese army came to be composed of recruits from the lowest stratum of Chinese society. Service as a soldier left an indelible social stigma. Because China then had what Lei termed a "soldierless civilization," during the second cycle of Chinese history the nation was conquered, either partially or totally, several times. In the late 1930's, the Sino-Japanese war having begun. Lei Hai-tsung moved with Tsinghua University to Changsha and then to Kunming, where it merged with Peking and Xankai universities to form Southwest Associated University. From the summer of 1940 to the summer of 1946 Lei served as chairman of the combined university's history department and taught medieval European history as well as Chinese history. In 1940 he and Lin T'ungchi, a political scientist, began publishing a fortnightly review called Chan-kuo ts'e. Its name was derived from the title of the annals of the Warring States. For a few months in 1941 the Chan-kuo ts'e also appeared monthly in Shanghai. Soon afterwards, the magazine ceased independent publication and became the Chankuo supplement of the leading new'spaper Ta Rung Pao. Through this organ, Lei's cyclic theory of Chinese history and his studies of Chinese culture reached a large audience. He and Lin T'ung-chi collected and published a number of their Chan-kuo articles in 1946 under the title Wen-hua hsing-Vai shih-kuan [historical views of cultural configurations].

Lei Hai-tsung served as chairman of the Tsinghua history department after the university returned to its Peiping campus in the summer of 1946. During the academic year 1946-47 he also served as acting dean of the faculty of arts and letters. Because Lei had opposed Marxism and had consistently supported the National Government as a unifying force in China, he was respected by such highranking Kuomintang officials as Chu Chia-hua (q.v.). In 1948 Chu, then the minister of education, persuaded Lei to launch a new magazine, the Chou-lun [weekly review]. That year, 44 issues of the magazine appeared. After the Chinese Communists gained full control of the mainland in 1949, Lei remained in Peking. In 1952 the Central People's Government transferred him to Nankai University in Tientsin. Lei's only comments on the new regime were made in his occasional reports on land reform, in which he was required to examine his past. He stated that it would be difficult for him to cast away his pre-Communist Chinese cultural heritage and his Western education. During the Hundred Flowers campaign, when intellectuals were encouraged to speak their minds. Lei did so at a conference of professors in the Tientsin area on 14 April 1957. He argued that genuine social sciences can flourish only in a capitalist society and that the "new social sciences" of Marx, Engels, Lenin, and Stalin were only applications of "capitalist" social sciences to the specific problems of the working class. He went on to say that Marxism and its offshoots had suffered from intellectual stagnation since the passing of Engels in 1895 and that, as a result, the "new social sciences" had degenerated into dogmatic creeds. Finally, he challenged the historical accuracy of Marx and Engels with reference to their view of ancient "slave society." Official reaction to Lei's attack on Communist ideology was swift and condemnatory. He was criticized in newspapers, scholarly magazines, and popular magazines and was forbidden to teach Chinese history. Although he was permitted to remain at Nankai University, his teaching activities were limited to one course in foreign historiography. Lei Hai-tsung died of a kidney ailment on 25 December 1962. He was survived by his wife, nee Chang Ching-fo, and his daughter, Lei Ch'ung-lei, who was a lecturer in English literature at Peking University.