Was everyone in rural tribes before Rome conquered or was there anything more?
[Edit] In relation to Europe I mean- I realise civilisation basically basically spread from China towards Rome already (at least I assume)
So, "civilization" is a pretty terrible term. It seems to be ranking different people in a way where "civilized" is good and developed and "uncivilized" is bad and primitive. In addition, by selecting some traits as necessary traits for a "civilization" we exclude people who might suit the term in other ways. For instance when I was an undergraduate the definition of "civilization" included writing, which excludes a lot of people we might want to let it. The Inca didn't have a writing system in the sense of making marks to transmit language, but they had a system of knots that transmitted information. By the time I was in graduate school I saw "writing" replaced by "complex record keeping" which is a little better. But you can see how drawing up a checklist of what qualifies as "civilization" is problematic.
With that said, when I was a teaching assistant for Early World History classes we used this list:
Monumental or civic architecture indicates some kind of communal awareness. Complex record keeping means things are organized and the organization is preserved. Complex social structure means we can see that some people had more importance than others, and there are multiple ranks - whether in government, religion, military, whatever. Division of labor and agriculture go together in that agriculture allows people to do things other than grow food, like build the monuments, keep the records, be the priests etc.
We also made the distinction between pristine civilizations and secondary civilizations. Pristine civilizations are communities that can check all the boxes without known contact with another civilization. The textbook we used (Worlds Together Worlds Apart) I think gave five pristine civilizations:
Some people like to list Egypt in there too. For your question, there are two important points. All of these developed more or less independently (so it's not the case that civilization began in China and spread west), and these developed a long time before Rome!
Sumerians show up around 4000 BCE. The Harappan cities around 3000 or so. The Chinese civilization I can't remember the name of sometime around 2000. The Olmec around 1600. The Chico, 3000.
Rome, by contrast, wasn't founded in tradition until 753 BCE. Archaeology shows us settlement a little before 1000 BCE. By the time the Romans showed up, the Sumerians were long gone, the Minoans had failed, the Mycenaeans collapsed, the Hittites were forgotten, and that's just civilizations geographically near Rome.
Rome itself developed its civilization from contact with the Greeks, from whom they got their alphabet among other things, as well as other cultures. The Greeks were heavily influenced by contact with Anatolian cultures that developed out of the Bronze Age Collapse, and so on. Rome is very much a late comer to the civilization game. Rome existed in a Mediterranean surrounded by people with different levels of civilization. Phoenicians (including Carthage), Greeks, Persians certainly rate the term "civilization." I would include the Celts, the Celtiberians and Iberians as well, and numerous other European populations.
Again, "civilization" is a terrible idea to apply to people, especially when we can't have a good understanding of a given group. For instance, if we stress the "complex records" thing, we are claiming to know complex records when we see them, and we might not, and it might be a bad thing to measure in the first place. But I think I've described the sort of taxonomy that shows up in books that do that sort of thing and given some direction for your specific question about Rome.
OP, I’m curious (and mods, feel free to delete this if it violates any of the rules), on what basis do you venture to suggest that civilization spread from China to Rome? Although there is evidence that Mediterranean explorers made it into the steppes of Asia BCE (although I do not know how far) I have never heard of a causal link between dynastic China and Roman (or Greek) civilization.