A Chinese Biographical Dictionary/Ch'ang O
140 Ch'ang O 嫦娥. The wife of Hou I, who is said to have stolen from her husband the drug of immortality and to have fled with it to the moon, where she was changed into a toad. This toad, which answers to our "man in the moon," is believed to swallow the moon during an eclipse. Ch'ang 0's name was originally 恒 (or 姮) Hêng, in reference to the line 如月之恒 "like the waxing moon" in the Odes; but as the Emperors Mu Tsung and Chên Tsung of the T'ang dynasty both had Hêng for their personal names, it was therefore changed to Ch'ang.