In the second year of his reign, Emperor Wen of Han abolished the crime of slander and evil words. “In ancient times, the court had a banner for proposing good and a post for criticism, to open the way of government and invite remonstrance,” he said.
“Now the law has the crime of slander and evil words. This makes the ministers afraid to speak their minds, and the ruler has no way to hear of his faults.” The edict is in the Records of the Grand Historian.