according to the American encyclopedia, intellectual depression refers to the people of the dark ages because the historians thought that it was a time where not a lot of education was being tough or innovation. most of the historians didn't realize that it was only the beginning of the middle ages that not much exciting stuff had happened. they just all grouped it together and called it the dark ages. when they gave it the name it originally meant it was a time of darkness where there was nothing that came out of it.