《史记·三十世家·齐悼惠王世家》
到悼惠王去世，哀王即位以后，魏勃专断政事，权力比齐相还大。
及悼惠王卒而哀王立，勃用事，重於齐相。
By the time after King Daohui passed away and King Ai took the throne, Wei Bo monopolized state affairs and had more power than even the prime minister of Qi.