楚王
In spring 618, Emperor Yang was killed in a coup led by his general Yuwen Huaji. Yuwen declared Emperor Yang's nephew Yang Hao emperor and soon abandoned Jiangdu, heading north back toward the eastern capital Luoyang, where Emperor Yang's grandson Yang Tong was declared emperor by a group of Sui officials. Before Yuwen departed Jiangdu, he sent messengers to Du, commissioning Du as the governor of Liyang Commandery. Du refused the commission, instead offering submission to Yang Tong. Yang Tong commissioned Du as the grand commandant of the eastern forces and created him the Prince of Chu.