 Following his brother-in-law Xiao Yu's advice, however, the emperor also sought further help from Princess Yicheng, who sent her husband a false report of a northern attack on the khaganate.Between this report and others informing him of the arrival of Chinese reinforcements, Shibi Khan lifted the siege and returned home.With credit for his salvation murky, the emperor followed the advice of Su Wei and others to renege on most of his extravagant promises of reward; he also returned to Luoyang and began planning another expedition against Goguryeo, causing still more disaffection throughout the army.