Who is Yu-fang from Wild Swans: Three Daughters of China and what is their importance?

Yu-fang is the author's grandmother. The name Yu means "jade" and Fang means "fragrant flowers". Yu-Fang is seen by her father as a way out of his dreary life. He arranges for her to be seen by an important general who asks to take Yu-Fang as his concubine when she is just fifteen. There's an elaborate ceremony and her family receives many gifts from the general. Yu-Fang believes she will be happy with him. He has supplied her with a house of her own and an allowance, and he often showers her with jewels. But after only a few days together following the "ceremony", the general leaves and is gone for six years.