Sun Bu’er (1124? – 1182? CE) is one of a group of female Taoist masters referred to as the Immortal Sisters. She was intelligent, well educated, wealthy and the mother of three children. Although she showed spiritual tendencies from her childhood, she only took up the formal study of the Tao when she was 51 years old. At the age of 63 she predicted the hour of her death, presented herself to her students and said farewell to them by reciting a poem.

The beginning of the sustenance of life
Is all in yin and yang.
The limitless can open up
The light of the great limit.
Diligently polished, the mirror of the mind
Is bright as the moon;
The universe in a grain
May rise, or it may hide.

Translation Thomas Cleary