Answer:
In the fifty-fifth year of Qianlong's reign in the Qing Dynasty (1790), four Anhui opera troupes from the south, Sanqing, Sixi, Hechun, and Chuntai (called the four Anhui opera troupes) came to Beijing one after another. The Hui class entered Beijing." The first Hui class to enter Beijing was "Sanqing", which mainly sang "Erhuang". Because of its rich voice and repertoire, it gradually overwhelmed the Qin Opera that was prevalent in Beijing at that time. Many performers from the Qin Opera class were transferred to the Hui class, forming a fusion of the two tunes of Hui and Qin. Subsequently, three other Anhui classes: "Sixi Class", "Chuntai Class" and "Hechun Class" also came to Beijing, causing the Kunqu Opera, which has been popular for many years, to gradually decline.
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