Answer:
it was based on a power struggle
Invasions of people--many of the groups came as military and fought the Romans as invading forces.
Counterclaim--they were migration patterns as they were attempting to gain access to an empire with advanced trade and education. Migrating to the Roman Empire gave a person or group with extra resources.
News and media coverage featuring the acts done by the terrorist groups or organization to the mainstream public audience. Say some attack happened in a local area and you see the details on the news, in result of this you will naturally be more aware and paranoid because of the fear of an attack happening to you. Its a scare tactic used to induce fear.
The government had agreed to stop funding Shinto, which those they made the treaty with hoped this would take power away from the Emperor. So Shinto became more of a culture thing instead of a religious thing.
