Yuwen Huaji
Yang Zhengdao was a member of the House of Yang, the ruling family of the Sui dynasty. His father Yang Jian was the Prince of Qi during Emperor Yang of Sui's reign. In April 618, a mutiny led by Yuwen Huaji massacred Emperor Yang, Yang Jian, and many members of the family while they were touring in Jiangdu. Empress Xiao (Yang Jian's mother) and presumably Yang Zhengdao's pregnant mother were among those spared. Yuwen Huaji seized them and took them north, but was in turn captured by the rebel Dou Jiande in 619. Dou Jiande killed him in the name of Sui and made the new-born Yang Zhengdao Duke of Xun.