《隋书·帝纪·卷一》
周明帝继位，授高祖为右小宫伯，加封大兴郡公。
明帝即位，授右小宫伯，进封大兴郡公。
When Emperor Ming of Zhou succeeded to the throne, he granted Gaozu the position of Right Junior Palace Director, and gave him the additional title of Duke of Daxing County.