Pei Ju
It is not known when Dai Zhou was born, and little is known about his family background, other than that he was from Xiang Province (相州, roughly modern Handan, Hebei—although Dai appeared to be from the part of Xiang Province now part of Anyang, Henan). He was said to be honest and capable. He studied law in his youth and was an excellent record-keeper. Near the end of the reign of Emperor Yang of Sui, he served as a low-level official in the examination bureau of the government (門下省, "Menxia Sheng"), and he was honored by both Su Wei and Pei Ju, the head and the deputy head of the examination bureau. In 618, after Emperor Yang was killed in a coup at Jiangdu (江都, in modern Yangzhou, Jiangsu), the Sui officials at the eastern capital Luoyang declared Emperor Yang's grandson Yang Tong the Prince of Yue emperor. Dai was slightly promoted in Yang Tong's administration, but remained relatively low in his position.