The cause is Feudalism
In feudalism system, normal citizens will work for the nobles in exchange of salary and protection.
Because of this, many people started to migrate into rural area where they will be given a certain amount of land by the nobles to be taken care of.
There would be no balance of power
War.
That is how most people would solve an argument. For example when British and French were fighting for Ohio the only way it could be solved is with war.
The Roman Forum was the center for almost all major events in Roman public life--holding prominent speakers, triumphant processions, and holding meetings between some of Rome's most powerful people.
