What are some terrible examples of illiteracy in history?

Chen Chong, who has no education, will flatter and praise Wang Mang's merits and call him "the Lord of Heaven". Chen Chong's "one trick" alone is enough to promote himself to a higher position and make a fortune, while Liu Adou, who is proficient in eating, drinking and being merry, does nothing but study. If he could learn from Zhuge Liang, he would not lose Liu Bei's hard-won land.