The Battle of Mobei was a military campaign fought mainly in modern-day Mongolia, in the extreme cold and barren lands of the Gobi Desert. It was part of a major strategic offensive launched by the Han dynasty in the winter of January 119 BC, into the heartland of the nomadic Xiongnu. The campaign was a success for the Han, whose forces led by Wei Qing and Huo Qubing reached as far north as Lake Baikal.