Hui

You may wonder isn't the Hui people (回族) descendants of the Uyghur Empire (回纥) ?

On that, you are wrong.

Most of the modern Hui people are descendants of Persian Muslim traders who settled in the Tang Empire. The Han (漢) people mixed them up with other tribes outside the Central Kingdom and gave a discriminating collective term: the Western Barbarians (西域胡人).

This group became even more heterogeneous when there came the Arabic, Mongol, Turkic (which shared the same origin as the Uyghur), Iranian, or other Central Asian settlers - mostly in the Yuan (元) dynasty.

By the way, most of the Hui people live in the Ningxia (寧夏) region now - while the original people from the Western Xia Empire (西夏), a branch of the Qiang tribe (羌族), has essentially disappeared on earth.

PS. You think all these irrelevant ?

May be. But, the eternal question is: What is relevant ?