There are very few words in China that are domineering enough to be called arrogant, such as words that are incomprehensible, which appeared in the Qin and Han Dynasties, "All the sun and the moon shine, and the rivers go to the Han soil." That's it. Where did ancient China get such great self-confidence?
There is a word called "heavenly round place", which is somewhat similar to the medieval foreigners' belief that "the earth is the center of the universe", when the ancients' understanding of the earth was not yet comprehensive, there was no specific concept of how large the territory of the dynasty was, and the division of the territory was not so fine.
At that time, it seemed that Huaxia was worshipped by all countries, because the land of agricultural civilization in East Asia at that time, and even the nomadic peoples were vassal states for a long time. This is also the reason why China's ancient wars with the Xiongnu or Goryeo regions will not be said to be invasions.
The ancients believed that the end of the world was just west of the Pamir Plateau, which meant that the whole world was so large. This seems to be wrong today, but at that time people thought that the world was like this. The "tianxia" mentioned by the ancients refers to the Central Plains Dynasty, when the Central Plains Dynasty fought invincible hands all over the world.
As the only civilization in the world that has not been interrupted, the Chinese civilization has its own self-confidence and pride. During the Qin and Han dynasties, China already had a perfect farming system and achieved self-sufficiency.