The government of China officially espouses state atheism, [3] though Chinese civilization has historically long been a cradle and host to a variety of the most enduring religio-philosophical traditions of the world. Confucianism and Taoism (Daoism), later joined by Buddhism, constitute the "three teachings" that have shaped Chinese culture. There are no clear boundaries between these intertwined religious systems, which do not claim to be exclusive, and elements of each enrich popular or folk religion. The emperors of China claimed the Mandate of Heaven and participated in Chinese religious practices. In the early 20th century, reform-minded officials and intellectuals attacked all religions as "superstitious", and since 1949, China has been governed by the Communist Party of China, an atheist institution that prohibits party members from practicing religion while in office. In the culmination of a series of atheistic and anti-religious campaigns already underway since the late 19th century, the Cultural Revolution against old habits, ideas, customs and culture, lasting from 1966 to 1976, destroyed or forced them underground.[4][5]:138 Under subsequent leaders, religious organisations were given more autonomy. The government formally recognizes five religions: Buddhism, Taoism, Catholicism, Protestantism, and Islam (though the Chinese Catholic Church is independent of the Catholic Church in Rome). In the early twenty-first century there has been increasing official recognition of Confucianism and Chinese folk religion as part of China's cultural inheritance.Folk or popular religion, the most widespread system of beliefs and practices, has evolved and adapted since at least the Shang and Zhou dynasties in the second millennium BCE. Fundamental elements of a theology and spiritual explanation for the nature of the universe harken back to this period and were further elaborated in the Axial Age. Basically, Chinese religion involves allegiance to the shen, often translated as "spirits", defining a variety of gods and immortals. These may be deities of the natural environment or ancestral principles of human groups, concepts of civility, culture heroes, many of whom feature in Chinese mythology and history.[6] Confucian philosophy and religious practice began their long evolution during the later Zhou; Taoist institutionalized religions developed by the Han dynasty; Chinese Buddhism became widely popular by the Tang dynasty, and in response Confucian thinkers developed Neo-Confucian philosophies; and popular movements of salvation and local cults thrived