One characteristic of Chinese art is the extent to which it reflects the class structure. Up to 221 BCE, the arts were produced by anonymous craftsman for the royal and feudal courts. Bronze sculptures were regulated by the court and could only be done by workshops which were approved to do so. During the Han dynasty landowners and merchants became patrons summoning paintings, calligraphy, poetry, music, and sculptures which enabled the educated of the lower class and the elite amateur artists to arise. Scholarly amateurs concentrated on visual arts which became a tradition and was admired by other amateurs and gentlemen. During the Chinese revolution, scholarly art and artists were looked down upon and the work of anonymous artists before 900 CE (Tang Dynasty) were emphasized again. The work of Chinese artist has been in a transformation from craftsman who were commissioned to do work, the artists coming out of workshops, and the scholarly were allowed to create artwork. The structure of art has also gone from doing work for the royal and feudal courts to work consisting of visual arts and also music.