Imperial consorts of Tang China are organized in eight or nine ranks, in addition to the empress. They are also called the "inner officials" (內官), as opposed to "palace officials" (宮官), the bureaucracy.
In 662, the titles were temporarily changed to be devoid of feminine and superficial quality. This seemingly feminist change was reverted in the twelfth month of 670. The rationales were not explained in official records in both instances. However, some scholars have speculated it to be the suggestion of Empress Wu to her husband.
For later history, see Ranks of imperial consorts in China.