to surrender. Suddenly, a thick fog descended over the scene, and Dou gladly stated, "The Heavens are helping us!" He then made a surprise attack on Xue's camp, causing Xue's army to panic and collapse. Xue fled back to Zhuo Commandery with less than 100 men, and died in anger there. Meanwhile, Dou continued to expand but, knowing that Li, then occupying modern central and eastern Henan, had the stronger army, he sent messengers to nominally submit to Li. In spring 618, after Li had a major victory over the Sui general Wang Shichong, whom Emperor Yang had sent from Jiangdu (江都, in modern Yangzhou, Jiangsu) to aid the eastern capital Luoyang, Dou, along with several other rebel leaders, sent a submission to Li, then carrying the self-declared title of Duke of Wei, urging him to take imperial title. Li declined. Meanwhile, Li's subordinate Fang Yanzao () wrote Dou, inviting Dou to meet Li to show his loyalty. Dou wrote back in humble and polite terms, but declined with the excuse that he needed to defend an attack from Luo Yi (a former Sui official who had seized Zhuo Commandery himself) from the north. (Later that year, Wang defeated Li, causing Li to flee west and surrender to Emperor Gaozu of Tang (Li Yuan), a former Sui general who had rebelled in 617 and established Tang Dynasty in spring 618, although he was eventually killed by Tang forces after attempting to reestablish his independence.) Soon, news arrived from Jiangdu that Emperor Yang had been killed in a coup led by the general Yuwen Huaji. The Sui official Wang Cong (), who had held out against Dou at Hejian, observed a mourning period for Emperor Yang, and Dou, in response, sent a messenger to Wang to express condolences. Wang then surrendered to Dou. As Wang had previously had several victories over Dou's soldiers, Dou's soldiers wanted Wang put to death, but Dou pointed out that Wang's faithfulness to Sui should be rewarded, and therefore made Wang a prefectural prefect. A number of other Sui commanderies also surrendered to him. He then began to organize his staff into a governmental structure, and he set his capital at Leshou (樂壽, in modern Cangzhou). In winter 618, after five large birds appeared at Leshou, with an assortment of over 10,000 small birds, and later left, Dou, believing them to be fenghuang (phoenixes), changed his