I realise many answers will argue that it has to do with Northern Europe’s location near the Atlantic ocean. However, Northern European countries by the late Middle Ages, and before the discovery of America, were already some of the wealthiest in the world. The actual origin of Europe’s wealth is surprisingly to be found in the Middle Ages.

So how did Northern Europe countries become so wealthy? Adam of Bremen in the 11th century describes Norway as being a poverty stricken land, which he explains as the primary reason for the Viking raids against Christian lands, writing “the extreme poverty of the Norwegians formerly impelled them to roam over the whole world: whence they brought back to their own land much wealth; the fruit of their piratical enterprises.” This also ties in to why Scandinavia eventually converted to Christianity, which is that they wanted the cultural, political and economic benefits that came with being part of “Latin Christendom.”

It’s interesting to note that historians of medieval Europe often treat the expansion of European Christian culture during the early and high Middle Ages as a protocolonial endeavour. Much of Central Europe was conquered or colonised by Christians, and the expansion of Europe’s frontiers came as a result of conquest, colonisation and mission.

As the civilisation of Latin Christendom further expanded in this medieval protocolonial endeavour, it created a flourishing during the high Middle Ages, when population, productivity, and wealth grew greatly and relatively quickly. That flourishing laid the foundations for European world dominance in the modern period, and the reasons for it are very complex and much discussed. The roots of Europe’s growth lay in the essentially agrarian society of the early Middle Ages, where the demands for revenue of lords (secular as well as ecclesiastical) and kings stimulated local markets as well as long-distance trade, agricultural improvements, and social reorganization. Whether Europe saw fundamental social changes clustered closely around the year 1000 (“the feudal revolution”), which would coincide neatly with the conversion of Scandinavian kings, or whether the changes played out more slowly over a longer time period, has been much debated over the past several decades. Much recent research has preferred to see a slow development of European society and economy, with deep roots going back, at least, to the Carolingian era, as exemplified by the surge of trade around the Baltic Sea in the Viking Age.

Anders Winroth states that during the centuries after 800, the area of western, Christian culture—of Latin Christendom—at least doubled, as it came to encompass much of eastern and northern Europe and, in due time, also the Iberian Peninsula. He argues that this was a momentous development; it caused the population of Europe to reach a critical mass, which made possible the great ascendancy of European civilization that continues to this day. That greater population laid the foundation for more intense land use, more commerce, the reorganization of government, the expansion of education, and military innovations, among the many developments of the high Middle Ages that make up the historical background of modern western society. Europe’s expansion (meaning that of Latin Christendom) during the centuries around the year 1000 was, thus, not only a precedent for Europe’s colonial expansion to other continents in the early modern period, but also a necessary precondition for it.

So beginning slowly in Carolingian times, European trade surged in the high Middle Ages, particularly in the areas around and between the two main trading poles: the cities of northern Italy and those of the Low Countries. The wealth and habits developed at that time would stand behind Europe’s economic world domination that lasted until the twentieth century.

Source: Anders Winroth, Conversion of Scandinavia