We've had many WIs about nations, empires or peoples conquering, expanding or migrating in different directions or ways than in OTL before, I know. I haven't seen one about the Ancient Greeks, though. So what if the instead of conquering, expanding and migrating eastwards and southwards, the ancient Greeks instead went westwards or northwards? How is this going to effect Greek civilisation and the world? What about the uncivilised tribes in the north? What does this mean for any future Roman Republic or Empire, if that is at all possible now?