Oh my Lord.
I hope, Schizm, that wasn't a real question? You need to do a little research. These cultures such China and the Olmec, Toltec, Aztec, Maya, Inca, not too mention the North American plains and pueblo cultures such as the Anasazi, and the pacific island cultures were all flourishing before the Roman Empire was ever a dream. At the height of the Roman Empire, there still lived vast numbers of tribes and lands and people from the Asiatic tribes, the Norsemen, Rus, Asian Countries, Sub-Saharan cutures of Africa, the Pacific Island nations and of course the Americas that either didn't even know of Rome or didn't care one flip.
The point of the scriptures is from the viewpoint of its writers. Thus in the Bible when it talks about the inhabited nations or when it talks about the 'good news being spread to all the inhabited nations" before the end (presumably the destruction of Jerusalem in 70 C.E.) comes, or even when it speaks about Noah's flood covering all of the Earth or wiping out all of the people and animals, etc. - all of these things should be understood to be limited to specific locality and not in fact to a global dimension. This was the "known" world to and for those Bible writers, they had no knowledge of the unknown parts of it or they would have included or dealt with such in their writing.
-Eduardo Leaton Jr., Esq.