Yuwen Tai
In spring 556, Yuwen Tai was pondering the issue of succession. His wife Princess Fengyi, the sister of Emperor Xiaowu of Northern Wei, had one son, Yuwen Jue, but he considered the fact of whether making Yuwen Jue heir apparent over Yuwen Yu would trouble Dugu Xin. On the advice of Li Yuan (), who argued that the son of a wife always had precedence over the son of a concubine, Yuwen Tai made Yuwen Jue his heir apparent. Yuwen Tai died later that year, and Yuwen Jue inherited his titles, under the guardianship of Yuwen Tai's nephew Yuwen Hu. In early 557, Yuwen Hu forced Emperor Gong of Western Wei to yield the throne to Yuwen Jue, ending Western Wei and establishing Northern Zhou (with Yuwen Jue as its Emperor Xiaomin but using the alternative title of "Heavenly Prince" ("Tian Wang")).