The Taiping Heavenly Kingdom developed a complicated peerage system for noble ranks.
King/Prince
Wang (王, lit. "king" or "prince") was the highest title of nobility, often hereditary, ranked just below the Heavenly King. There were five ranks of wang:
Non-hereditary nobility ranks
Below the king or prince, there were six ranks of nobility () in Taiping Heavenly Kingdom: E (義 Yì), An (安 Ān), Fu (福 Fú), Yen (燕 Yān), Yü (豫 Yù) and Hou (侯 Hóu). The nobility titles were not hereditary.
E and An were most highest ranks of the nobility, once they were very noble titles of the Taiping Heavenly Kingdom. If the Heavenly King wanted to promote someone, he gave the person either E or An. However, this rule was challenged after 1860 because the nobility titles had been given too freely.