《晋书·志·第十一章》
皇妃皇后虽然是国君配偶的名称，然而自皇后以下有夫人和九嫔，没有称作妃的。
妃后虽是配君之名，然自后以下有夫人九嫔，无称妃焉。
Although empress and queen are titles of the spouses of emperors, there are consorts and nine concubines below the empress, none of them are called concubines.