The death of Emperor Zhang in 88 and the succession of his ten-year-old son Emperor He brought significant changes to the political landscape. The regents of the young emperor, Empress Dowager Dou and her brother Dou Xian, favoured a more militaristic policy to the Northern Xiongnu problem. Both their regional background and position at court encouraged them to seek the expansion of central authority through war. With the Grand Commandant Su You, Minister of Works Ren Wei () and the Nine Ministers, Yuan An marched on the court hall and submitted memorials condemning a campaign in the north. He argued that since the Northern Xiongnu had not invaded the frontier, there was no reason to waste resources on a distant expedition. Despite his strong opposition and that of other conservative advisors, Lady Dou ordered the dispatch of an expeditionary force. In the summer of 89 a Chinese-led force advanced in three columns with minimal opposition and defeated the Northern Shanyu at Jiluo Mountain and pursued him westwards into the Altai ranges. A final offensive in 91 destroyed the Northern Xiongnu, creating a political vacuum in its former territories which the Han empire would struggle to contain in the next two centuries.