After two thousand years the farmers’ culture reached the shore of the Western Ocean – but here the wave broke. If the Northlanders had not existed, perhaps the farmers and their culture would have colonised the shore lands and islands of the ocean fringe. But Northland, though still a culture living off the produce of the wild earth, was literate, technically advanced, strong, self-confident. The Northlanders traded and learned, but farming held no interest for them.

Again the climate shifted, with a spasm of drought heralding a new age of warm, dry conditions; again humanity’s fragile cultures flowed and changed in response. In the east the farming communities coalesced into a new phenomenon: towns and cities, major gatherings of population, centrally controlled, dedicated to the great task of maintaining complex nets of irrigation channels in increasingly dry landscapes. Empires bloomed like fungi on a log. Soon trading routes spanned the Continent, carrying amber from the north, silver from the south, timber from the west, tin and lapis lazuli from the east. Bronze was everywhere, in cups and ornaments and statuary, in the body armour and swords of the new warrior kings. The traders and warriors probed west and north, seeking profit and conquest. But again the old Northlander culture stood strong, and older ways were preserved.

And still the earth would not rest. Over an ocean on the far side of the world, elaborate cycles of heat and moisture collapsed, resumed – changed. The consequences rippled across the continents, in more waves of flood and drought, famine and disaster.