Triad Society, name given to a number of Chinese antidynastic secret societies by 19th-century Western observers. Most of these groups claimed descent from the Heaven and Earth Society (Taendi hui) or the Triad Society (Sanhe hui), two secret societies of the late 17th cent. that had originated in Fujian prov. The avowed purpose of these societies was to overthrow the alien Manchu Ch'ing dynasty and to restore the native Chinese Ming dynasty. Societies sharing a similar ideology, ritual, and terminology spread all along the SE China coast. In times of peace the secret societies functioned as fraternal organizations, but they often became involved in criminal activities and at times armed conflict with rival groups occurred. Poor peasants, itinerant workers, and others who lacked strong kinship ties found security in the fraternal ties and in the protection offered by the societies. The Taiping Rebellion (1850–64) brought a revival of secret-society militancy and anti-Manchu sentiment, but local groups continued to function independently and no hierarchic organization was achieved. Branches of the Triads assisted Sun Yat-sen and other revolutionaries to carry out armed insurrection against the Ch'ing dynasty in the decade before the republican revolution of 1911. The Communist government of China launched (1949–50) a campaign to eliminate secret societies soon after assuming power. Triad societies persisted outside mainland China and among overseas Chinese. For the activities of secret societies in N China during the Ch'ing period, see White Lotus Rebellion; Boxer Uprising.