Empress Erzhu (Yuan Ziyou's wife)

In historical texts, she's often referred to by her final title of Princess Dowager of Pengcheng (彭城太妃).

Lady Erzhu's father Erzhu Rong had been a hereditary chief of the Qihu (契胡) tribe, a branch of the Xiongnu, located at Xiurong (秀容, in modern Shuozhou, Shanxi), and during the agrarian rebellions during Emperor Xiaoming's reign had become increasingly powerful as a military general.

Erzhu Rong refused to recognize the young emperor Yuan Zhao that she put on the throne, instead advancing on Luoyang, capturing it and throwing Empress Dowager Hu and Yuan Zhao into the Yellow River to drown.

Emperor Xiaozhuang initially hesitated, as pursuant to Confucian regulations he would be committing incest if he did.

[4] In spring 545, Lady Erzhu's brother Erzhu Wenchang (爾朱文暢) and Zheng Zhongli (鄭仲禮), the brother of Gao Huan's other favorite concubine Zheng Dache (鄭大車), along with Ren Zhou (任冑), conspired to assassinate Gao Huan and support Erzhu Wenchang as leader, but the conspiracy was discovered, and the conspirators were put to death, along with their families.

However, because of Gao Huan's favors for Lady Erzhu and Zheng Dache, he spared their brothers.