I'll use Wikipedia for part 1.
Most people under Roman rule were slaves. Slavery was deeply connected to the Roman identity. This belief was one of the foundations of their society. Basically, their gods told them to dominate weaker people. Sounds familiar? Perhaps that explains the dominating nature Christianity later took under Roman rule.
https://en.m.wikipedia.org/wiki/Slavery_in_ancient_Rome
Secondly, the Vikings were the result of hundreds of years of dealing with Romans. Romans, unlike most empires, dominated people and erased their history amd culture. Sounds familiar? They also practiced wholesale slavery of dominated cities. Imagine if it were your daughter.
"Viking" people were reacting to an unnatural slaughter, and adapted extreme violence as survival. However, as someone else pointed out, without Roman pressure, they have reverted back into some of the most peaceful/progressive people in the world.
Also, Viking, as noted is a modern creation. I used the group as as identifier because it's a common group known to you. If you really want to be technical, the area that came to be Viking was never one culture, and had many groups and languages coexisting peacefully, just like the people of the Caribbean before domination.
Funny how a anti-"white" person like me, constantly praises the "whitest" people in the world. Maybe Saad my problem is just with US and UK based idiots. The type of idiot who constantly advances a violence based world view because they are part of the bullying group.
So, you're high school works history, which reinforces 1800 racism is a joke.
