杜如晦
In 619, with the Sui state collapsing in light of rebellions around the empire before and after Emperor Yang's death in a coup in 618, the general Wang Shichong, in control of the eastern capital Luoyang, deposed the last Sui emperor, Emperor Yang's grandson Yang Tong and declared himself emperor of a new state of Zheng. Wang made Du Yan the minister of civil service affairs and trusted him greatly. Meanwhile, Du Yan's nephew Du Ruhui had become an important advisor to Li Shimin, a son of rival Tang Dynasty's Emperor Gaozu and a major Tang general. Du Ruhui's older brother (whose name is lost to history) and younger brother Du Chuke () were at Luoyang at that time, under Zheng rule. Du Yan had poor relations with his nephews, and he decided to act against them. He falsely accused them before Wang, and Wang executed Du Ruhui's older brother and imprisoned Du Chuke. Du Chuke almost starved to death but survived the imprisonment.