The area that became Scotland in this period is divided by geology into five major regions: the Southern Uplands, Central Lowlands, the Highlands, the North-east coastal plain and the Islands. Some of these were further divided by mountains, major rivers and marshes. Most of these regions had strong cultural and economic ties elsewhere: to England, Ireland, Scandinavian and mainland Europe. Internal communications were difficult and the country lacked an obvious geographical centre. Dunfermline emerged as a major royal centre in the reign of Malcolm III and Edinburgh began to be used to house royal records in the reign of David I, but, perhaps because of its proximity and vulnerability to England, it did not become a formal capital in this period.