with it. The most important set of music of the period was the Six-dynasty Music Dance (六代樂舞) performed in rituals in the royal court. Music in the Zhou Dynasty was conceived as a cosmological manifestation of the sound of nature integrated into the binary universal order of yin and yang, and this concept has had an enduring influence over later Chinese thinking on music. "Correct" music according to Zhou concept would involve instruments correlating to the five elements of nature and would bring harmony to nature. Around or before the 7th century BC, a system of pitch generation and pentatonic scale was derived from a cycle-of-fifths theory. Chinese philosophers took varying approaches to music. To Confucius, a correct form of music is important for the cultivation and refinement of the individual, and the Confucian system considers the formal music yayue to be morally uplifting and the symbol of a good ruler and stable government. Some popular forms of music, however, were considered corrupting in the Confucian view. Mozi on the other hand condemned making music, and argued in Against Music (非樂) that music is an extravagance and indulgence that serves no useful purpose and may be harmful. According to Mencius, a powerful ruler once asked him whether it was moral if he preferred popular music to the classics. The answer was that it only mattered that the ruler loved his subjects. In ancient China the social status of musicians was much lower than that of painters, though music was seen as central to the harmony and longevity of the state. Almost every emperor took folk songs seriously, sending officers to collect songs to record the popular culture. One of the Confucianist Classics, The Classic of Poetry, contained many folk songs dating from 800 BC to about 400 BC. Qin to Qing dynasty The Imperial Music Bureau, first established in the Qin dynasty (221–207 BC), was greatly expanded under the emperor Han Wudi (140–87 BC) and charged with supervising court music and military music and determining what folk music would be officially recognized. In subsequent dynasties, the development of Chinese music was influenced by the musical traditions of Central Asia which also introduced elements of Indian music. Instruments of Central Asian origin such as pipa were adopted in China, the Indian Heptatonic scale was introduced in the 6th century by a musician from Kucha named Sujiva, although the heptatonic scale was