《旧唐书·本纪·卷十一》
二十六日，河西党项、永、定等十二个州部落归附，请求设置宜、芳等十五个州，皇上同意了。
戊子，河西党项永、定等十二州部落内属，请置宜、芳等十五州，许之。
On the 26th, the 12 states and tribes of the Tangut in Hexi, Yong, and Ding submitted, and requested that 15 states be established, which the Emperor agreed to.