So let me get this this straight. I'm going to use examples to explain how I understand.
Now for land wise, between an Emperor and a King, I'm going to try to compare it to now, using federal government (like the USA) in comparison.
*KEY*
RED = THEN
GREEN = NOW
KING
A Governer is like a King. But without the President. Because theirs a Governer for each state in the USA, just like a king owns a piece of land, and has many other kingdoms, under control of other kings, surrounding? (Maybe not as much kingdoms as states in the USA)
EMPEROR
The President of the USA is like a Emperor, but without any governers?
Understand me? yes, no? or wtf?