Marrying daughters of the Han imperial family to the rulers of the minority groups was one of the foreign policies of pacification in the Western Han Dynasty (206BC-8AD). The policy had gone through two stages. At first, Han rulers took the initiative to marry daughters of the royal family and offer valuables of all kinds so that the Huns could stop harassing the northern border of the empire. When Emperor Wudi was in power, it was the Huns who proposed to Han for marriage.
In the reign of Emperor Wudi, substantial resources were available to him as a result of his own successful policies as well as those of his predecessors. Consequently, he was in a position to take an active and offensive stand against threats of invasion. He sent three expeditions led by Wei Qing and Huo Qubing against the Huns in 127BC, 121BC and 119BC respectively. By these actions, he drove them into the far north of Gobi, thus maintaining the safety of the Hexi Corridor. The threat from the Huns was resolved; however, they did not reach an agreement on the issue of the policy of pacification through marriage.
During the reign of Emperor Xuandi, the Huns was already in decline. And the ruler Huhan decided to pledge allegiance to Han by sending his son to Han as a promise.Emperor Yuandi, to further a good relationship between the Huns and the Han people, married Wang Zhaojun, a beauty at that time, to the Khan. This action not only stabilized the relationship between the Han Dynasty and the Huns, but promoted economic and cultural exchanges between them.
Meanwhile, Han also marry daughters of royal families to rulers of Wusun tribe for pacification. In 71BC, Han in alliance with Wusun tribe gave the Huns a fatal defeat from which it never recovered.
The policy of marriage for pacification was an important policy helpful to the economic and cultural exchanges between Han and minority groups.