Why do you think that the Romans could unify their peninsula and Greece could not?

Greece would have had a much harder time with unifying their area because each city had its own government and pretty much did its own thing. For example, Sparta and Athens were both Greek cities, but their governments were totally different and it would have been hard to unify them. Greece cities were also pretty isolated because there are a lot of mountains, and other difficult geography, and it was hard to get from one city to another.