Just read the research. And I didn't say the UK existed, I said the market existed across the UK (if you read the research, you would know that price integratio

Just read the research. And I didn't say the UK existed, I said the market existed across the UK (if you read the research, you would know that price integration has been proved across medieval England, Wales, and Scotland i.e. what is the UK today). And yes, but neither the Javanese or the Maori grew grain (the Maori were still nomadic in this period, growing grain would have made no sense). Again: the integration has been proved for the grain markets that existed around Western Europe, the Baltic regions (and Asia if you consider Russia in this period), north Africa, and the Levant i.e. the global grain market that existed in medieval periods. No, this doesn't include China, where there was substantial internal trade in this period, but this doesn't seem to be a huge difference.