《汉书·传·郦陆朱刘叔孙传》
中原人数以亿计，地方万里，处在天下最富饶之地，人民众多，车马繁盛，万物富庶，政权统一，自开天辟地以来未曾有过。
中国之人以亿计，地方万里，居天下之膏腴，人众车舆，万物殷富，政由一家，自天地剖判未始有也。
The people of the Central Plains numbered in the hundreds of millions, the territory extended over ten thousand li, it was located in the most fertile land in the world, the people were numerous, the carriages and horses were prosperous, all things were abundant, the political power was unified, which had never happened since the beginning of the world.