As I read on this page,

http://www.ivorcatt.com/3101.htm

Quote Start:

Among the Volga Bulgars, Ibn Fadlan found a strange custom:

“When they observe a man who excels through quickwittendess and knowledge, they say: ‘for this one it is more befitting to serve our Lord.’ They seize him, put a rope round his neck and hang him on a tree where he is left until he rots away ....”

Commenting on this passage, the Turkish orientalist Zeki Validi Togan, undisputed authority on Ibn Fadlan and his times, has this to say: ‘There is nothing mysterious about the cruel treatment meted out by the Bulgars to people who were overly clever. It was based on the simple, sober reasoning of the average citizens who wanted only to lead what they considered to be a normal life, and to avoid risk or adventure into which “Genius” might lead them.’

Quote End.

How true is the recording of this strange custom? How prevalent was it? How would such an anti-intellectual society survive for multiple centuries?