班昭
However, this system did not cover all social groups while the distinctions between all groups became blurred ever since the commercialization of Chinese culture in the Song dynasty (960–1279 CE). Ancient Chinese education also has a long history; ever since the Sui dynasty (581–618 CE) educated candidates prepared for the imperial examinations which drafted exam graduates into government as scholar-bureaucrats. This led to the creation of a meritocracy, although success was available only to males who could afford test preparation. Imperial examinations required applicants to write essays and demonstrate mastery of the Confucian classics. Those who passed the highest level of the exam became elite scholar-officials known as "jinshi", a highly esteemed socio-economic position. A major mythological structure developed around the topic of the mythology of the imperial exams. Trades and crafts were usually taught by a shifu. The female historian Ban Zhao wrote the "Lessons for Women" in the Han dynasty and outlined the four virtues women must abide to, while scholars such as Zhu Xi and Cheng Yi would expand upon this. Chinese marriage and Taoist sexual practices are some of the rituals and customs found in society.