Answer:
Oligarchy refers to a form of power structure where most of the power/influences in a certain country is held by a really small group of people.
In the past, this is the dominant form of government in almost all nations. Common people probably know them better as the 'nobles' ,These people are the one that made all the laws and economic decisions. The common people on the other hand, were just there to obey them without able to do anything about it.
This led to a situation which caused a lot of suffering for the common people. The high taxes that that the nobles imposed made it impossible for the people to obtain enough money to buy their own food. In the end, many of them starved to death.
This led to massive revolutions to got rid of the oligarch and replace them with a democracy. In which , the people will have the most power to determine which laws can be passed in their country. (through votes)
This is basically how the power from oligarchy got taken away.
