《汉书·传·王莽传中》
又说道： 天上没有两个太阳，地上没有两个国王，这是百代帝王不能改变的原则。
又曰： 天无二日，土无二王，百王不易这道也。
Also said: There are not two suns in the sky, and there are not two kings on the earth, which is a principle that no sovereign can change throughout history.
<s>[INST] Kindly elucidate the central themes in this passage in English: 又曰： 天无二日，土无二王，百王不易这道也。 [/INST] Also said: There are not two suns in the sky, and there are not two kings on the earth, which is a principle that no sovereign can change throughout history.</s>
Kindly elucidate the central themes in this passage in English: 又曰： 天无二日，土无二王，百王不易这道也。
user
Also said: There are not two suns in the sky, and there are not two kings on the earth, which is a principle that no sovereign can change throughout history.
assistant