Why did the early Chinese call their land "Zhongguo"?

The early Chinese called their land Zhongguo, meaning "Middle Kingdom", because they felt that they were highly civilized and other inhabitants near China were considered barbarians. Therefore, they had that feeling of being superior over other civilizations. In my opinion, their philosophies and form of government influenced them in having that such kind of perspective. The Chinese would always want an efficient form of government, so there is a tendency that they will have the notion of being civilized people due to their stringent laws and centralized administration.

Source of photo: Google