By the early days of the Republic of China, Xiangsheng had evolved into a more modern format. It was performed in teahouses, theaters, and, eventually, on radio and television. There are three major sources of Xiangsheng: Beijing Tianqiao, Tianjin Quanyechang, and the Nanjing Confucius Temple. The origins of certain modern-day Xiangsheng pieces can be traced back well over 100 years, though in many cases, the original author is unattributed. Many skits in "traditional Xiangsheng" have evolved through generations of performers successively revising material, retaining the general structure or "heart" of a piece while updating specific references with more modern material. One of the earliest Xiangsheng pioneers is a person known by name of Zhang Sanlu (), who performed during the mid-19th century. Originally a performer of Ba Jiao Gu (drum-song) (), Zhang eventually switched to doing imitations and telling humorous stories. Later artists considered Zhang to have been one of the first Xiangsheng performers. Xiangsheng in Chinese Mainland After the establishment of the People's Republic of China in 1949, the popularity of Xiangsheng increased. Previously seen as relatively low-class street performing, Xiangsheng became regarded as a proletarian art form. Because it was performed in Mandarin Chinese, Xiangsheng became a useful tool for promoting the use of Mandarin Chinese throughout China. In the 1950s, Hou Baolin led a group of Xiangsheng performers to reform Xiangsheng, removing language and content that was considered "vulgar" and generally making it more "politically correct". Hou later became widely regarded as a master of Xiangsheng. He is often regarded as "China's Charlie Chaplin". As with many forms of performance art, Xiangsheng was banned during the Cultural Revolution. It experienced a huge resurgence in the mid-1970s, with many skits satirizing the Gang of Four and excesses of this period. With the popularization of television in the 1980s, Xiangsheng became a standard feature of the annual New Year's Gala of China Central Television (CCTV), as well as other popular performing arts shows in China. Xiangsheng entered a period of decline in the 1990s, caused largely by increased official sensitivity towards political and social satire following the 1989 Tiananmen Square protests, as well as the lack of performance venues outside of sanitized state-run television programming. Many performers called for a return of performing Xiangsheng in teahouses and small theaters, which had traditionally been the main venues for Xiangsheng performances but were almost never used at the time. A new