Chinese characters of Empress Wu

The Chinese characters of Empress Wu, or the Zetian characters (Chinese: 則天文字; pinyin: Zétiān wénzì), are Chinese characters introduced by Empress Wu Zetian, the only empress regnant in the history of China, in order to demonstrate her power. The characters were not created by the Empress herself, but were suggested by an official named Zong Qinke, the son of one of her cousins, in December, 689 AD. The number of characters varies between 12, 17, 19, or 30.

Source: Wikipedia — Chinese characters of Empress Wu (CC BY-SA 4.0)