I have seen a number of threads about the possibilities of a non-Mediterranean culture developing similarly to Greeks, Carthaginians, Romans, etc, but I understand that for such civilizations to rise, you need an urbanized culture developing complex religion, writing and agriculture. Due to the climate and the terrain, this is not really plausible in Northern Europe (present day Germania, Gaul, Pannonia and beyond). The land is too forested, so centralization is harder and big cities are less likely appear, as well as countless other factors. But what about the Celts in Cisalpine Gaul? They have contact with Greeks and other, more developed Italian cultures, rule an excellent area for agricultural development and for cities built around trade. Does this have potential?