Emperor Taizong of the Northern Song dynasty sought to take advantage of the situation by launching an invasion on the Liao dynasty's southern capital (present-day Beijing) in the contentious Sixteen Prefectures in 986. Three large Song armies were sent to three different strategic locations on the approach to the southern capital. While initially successful, the young Emperor Shengzong, along with Empress Dowager Xiao, led an army of Liao cavalry to counter the enemy and defeated the Song forces at the Battle of the Qigou Pass in June. Empress Dowager Xiao appointed Yelü Xiuge as her senior general to continue attacks on the Song dynasty in retaliation until the following year.