Rome took whatever they wanted because it's what those who lust for power often to. They don't ask, they don't say please, they show up with a legion of armored men, kidnap kids, kill anyone who tries to interfere, and they say this is all mine.
As for power, there were many tribes still then, many independent city states, not a lot of consolidation unless someone like Rome decided to take it all. Even the Greeks lacked a centralized power and the independent city-states often made war with each other. But it wasn't Greek vs Greek as we'd see it, it was Athenians against Spartans against Corinthians against Thebans.
Well I don't know if I want to paint all those people with such a broad brush. I don't know that I'd want somebody 2000 years from now to paint me that way, as a american. There were Romans and romans, I'm sure, just like there are Americans and americans. I'm sure there were powerful warhawks, and peaceful peasants, and everything in-between. I get a pretty cosmopolitan sense of Rome when I do read on it sometimes, brutal incidents aside.
What was manly about the vikings? Some were explorers, but most where *****es who preyed on the weak. Seriously, they raided monasteries and picked on monks amd nuns. And to confuse things further, most of us Euro-Americans glorifying them isn't much different than Jews glorifying the Nazis in a thousand years.
Well all I know is that they are interesting to read about, because there is a good hunk of non-Abrahamic written material to look at with them. As well, I'm not even sure that their myths contain much which is better or worse morally than what you get in the bible. I don't think I read anything in there was quite as bad as Deuteronomy 13, for example.
And I read bede, so I can point out a couple spots in there where the christians are described doing things that pretty comparable to anything the vikings may have done. For example, in book IV of the Ecclesiastical History of England
, chapter 16 is entitled "How the Isle of Wight received Christian inhabitants, and two royal youths of that island were killed immediately after Baptism."
As far as any ancient religion or wisdom tradition goes, I am unattached directly to any of that, but see that there are little nuggets of ideas here or there, that can endure or be reinterpreted. And those good ideas can come from almost anywhere. Plenty of secular people probably like something about the book of Job. There are some good sayings in the Norse Havamal, if you discard the few that might be about war. Seneca, the teacher or Nero, was great souled, and didn't share Nero's tyrant attitude about things.