The literary inquisition (), also known as speech crime (以言入罪), refers to official persecution of intellectuals for their writings in China. The Hanyu Da Cidian defines it as "the ruler deliberately extracts words or phrases from intellectual's writings and arbitrarily accuse him in order to persecute him" ("旧时谓统治者为迫害知识分子,故意从其著作中摘取字句,罗织成罪"). The inquisition took place under each of the dynasties ruling China, although the Ming dynasty was particularly notorious for the practice. In general, there are two ways a literary inquisition could be carried out. First is that the conviction came from the writing itself. That is, the writing was the direct cause of the persecution. The second is that the writing was used as a tool to provide legitimate evidence for a predetermined conviction. Such persecutions could owe even to a single phrase or word which the ruler considered offensive. Some of these were due to the naming taboo, such as writing a Chinese character that was part of the emperor's personal name. In the most serious cases, not only the writer, but also their immediate and extended families, as well as those close to them, would also be implicated and killed. The earliest recorded literary inquisition occurred in 548 BC in the state of Qi during the Spring and Autumn period. Recorded in the Zuo zhuan, the powerful minister Cui Zhu (崔杼), who had murdered the ruler Duke Zhuang, killed three court historians (Taishi, 太史) because they insisted on recording the event in the official history. The burning of books and burying of scholars in the Qin dynasty is also considered a form of literary inquisition by some Chinese scholars. It is uncertain how frequently the persecutions occurred. However, compared to during the Ming and Qing dynasties, literary inquisition before the Song dynasty happened less frequently due to the lack of printing. One major case during the Han dynasty was that of Yang Yun (杨恽). Emperor Xuan first discharged him from his position in the government under the accusation of defamation.