The policy of keeping on good terms with rulers of minority nationalities in the border areas by marriage started from Han Dynasty. It was diplomatically an expedient measure in feudal dynasties, i.e. to make minor sacrifices to safeguard major interests when facing powerful enemies. The peaceful time gained in such a way was used to recuperate and build up energy and develop economy. In Tang Dynasty, the policy was expanded to any pacification purpose. According to the statistics, the Tang rulers had applied its special marriage policy for 28 times respectively to such ethnic groups as Tu Jue, Tu Gu Hun, the Tibetan Regime then, Xi, Khitan, Ning Yuan Kingdom, Hui He and Nan Zhao Kingdom. The practice contributed greatly to the stability and prosperity of Tang Dynasty.
