What is "jiandi"

Jiandi , also with variants 簡易/简易 and 簡逷/简逷, is an important figure in Chinese history and in Chinese mythology. She was the second wife of Emperor Ku, who was a descendent of the Yellow Emperor. Jiandi was the mother of Qi, the predynastic founder of the Shang dynasty (note that this is a different Qi than the Qi Ji born to Di Ku's first wife Jiang Yuan). Her pregnancy miraculously occurred following her swallowing or holding in her bosom the egg of a bird. Jiandi was said to be of the Yousong clan. Jiandi is mentioned in various sources, including the poems "Eulogy of Shang", in the Shijing, and the " Heavenly Questions" in the Chuci.