The only answer I found was: The ancient Chinese kings maintained control of their dynasties throguh military means.
You probably go to connections accademy. I do too.
This question is in the Journey Across Time text book on page 231. The answer is on pages 225 - 231.
Besides the two answers above me, I managed to find a reasonable answer:
"Rulers became powerful because they controlled land and had strong armies."
This is all I could find, hope this benefits others who wonder what the answer is!
Well, it allowed them to garrison more troops there which led to an increase in slave commerce for the portugesse traders.
Some white abolitionists worried about the effect free African Americans would have on society. The American Colonization Society then planned to send free African Americans to Africa to start new lives.
HOPE THIS HELPED!!! XD
Charlemagne made Christianity the religion of the empire.