 In 90 BC, when Li was campaigning in the north against the Xiongnu Empire, his wife was imprisoned in the capital after being involved in a political scandal involving their in-law Liu Qumao (one of Liu's sons had married one of the Lis' daughters).Li sought a quick victory, hoping to win his wife's release.He overextended his army and was decisively defeated by a Xiongnu army of 50,000 led by their Chanyu Hulugu.