Xi Ping was Zhou Ying's cousin—the son of his mother's older brother. They grew up close, and Xi Ping was Zhou Ying's study companion for some years. Xi Ping did not stand on ceremony with Zhou Ying, despite his cousin's status as prince, and would go running to Prince Zhuang Manor whenever he got into trouble.1
Xi Zhengde, the Marquis of Yongning, was Zhou Ying's uncle—his mother's elder brother. The Marquis was mindful of Zhou Ying's position as Prince, careful to uphold boundaries of respect between them. This enabled Xi Ping to use Zhou Ying's home as a refuge, as his father couldn't brashly pursue him there.1