In the tenth year of the Zhangwu Era, Emperor Zhaowu Liu Bei launched a campaign against the various Hu peoples, an achievement later historians hailed as the greatest accomplishment of his life apart from unification.
Unlike Gaozu of Han, who encountered the Siege of Baideng after unification, Liu Bei saw the nation's strength gradually enter its golden age after unifying the realm.
Later historians calculated that after more than twenty years of chaotic warfare, the Han Dynasty's population had fallen to fewer than thirty million.
Yet within fourteen years of Liu Bei proclaiming himself king, the Han Dynasty's population had grown to as many as forty-seven million.
Moreover, unlike the era of Emperor Ling of Han, when internal troubles and foreign threats abounded and court revenues dwindled, the development of industry, commerce, and technology gave Emperor Zhaowu Liu Bei sufficient confidence to wage wars abroad.
On this foundation, Liu Bei's northern campaign was later recognized as the Han Dynasty's first deliberate war of aggression.
Contrary to Emperor Wu of Han's northern campaigns, which aimed to drive out the Hu invaders, Liu Bei's sole purpose in this war was to obtain enough slaves.
Thus, under the organization of Chancellor Qin Tian and the Ministry of War, the Han Dynasty mobilized a total of one hundred thousand iron cavalry. A special troop type that would influence later generations for a full two hundred years also emerged in this war.
Lancer cavalry—an age-spanning force equipped with horseshoes and saddles, possessing tremendous mobility, and wielding matchlock muskets instead of ring-pommel sabers as their primary weapons—came to dominate the entire battlefield.
It all began with Kebineng's death. Since Kebineng died in the fourteenth year of the Jian'an Era, central Xianbei had fallen into internal strife.
At this time, the Budugen faction in western Xianbei, previously