Storm in the Northern Song Dynasty

We compare ourselves to China and regard ourselves as the Celestial Dynasty, but during the Song Dynasty, Chinese civilization had to tremble under the iron hooves of foreigners, and the king of our great country was just like a minister of barbarians. It turns out that the so-called Heavenly Kingdom has long become a rhyme in our dreams, and the backbone of my Han people is no longer so straight. So when did we start to lose our glory? It should be in the Song Dynasty. If so, then let me wait and change history!