Du Yu
The Chu capital at Ying suffered an attack by the State of Wu in 506 BCE whereupon King Zhao of Chu fled to Sui. Although under pressure from Wu, Sui would not hand over King Zhao and protected him well. For this reason Sui was rewarded by Chu. For the year 494 BCE the Spring and Autumn Annals records: "The Prince of Chu, the Marquess of Chen and the Marquess of Sui attacked the State of Cai". Based on the History of Lu section of the same book later author Du Yu believed that Chu restored Sui's independence as a marquessate in return for their protection of King Zhao.