 Zang Tu had been named king of Yan by Xiang Yu, secured his title by removing its previous occupant Han Guang by force, and been confirmed in Yan and Liaodong by Liu Bang.Before the end of 202, however, he rebelled against the new empire and invaded its central northern commanderies, collectively known as "Dai" from a former kingdom of that name, which lay to his west in what is now northern Hebei and Shanxi.Chen Xi resisted Zang in Dai and helped the emperor's push into Yan, where Zang Tu was captured, executed, and replaced with the emperor's long-time comrade Lu Wan.