Asap who ruled the tyrants? who ruled the oligarchy's? who ruled the democracy? how did the monarchy's get their power? how did the monarchy keep their power? how did the oligarchy's keep their power?

1. oligarchy 
2. Puritan church
3. dont know sorry 
4. Feudal monarchs gave power to the military and nobles. With the use of these two, they were able to attack and control many lands around the area. They could also continue to hold these lands as long as he fed and payed the troops properly.
5. dont know sorry 
6. They get power the same way anyone else does. Keeping it is the hard part. They have to convince everyone that they are working on the behalf of everyone.

I'm just gonna answer this
The answer is C.The Roman Empire collapsed because its borders became too large to effectively defend.