In recent weeks, the massive arrival of asylum seekers opened a debate about the economic and political repercussions of immigration in Europe. The discussion is not entirely new. Traditionally, migrations in and out of Europe have shaped the Continent. Merchants, artists and intellectuals moved between European countries to practice their trade. British, Dutch, Germans and Swedes also immigrated to the United States, while Spaniards and Italians sought South America. Europe has had its fair share of population displacements as well: Russians moved to Western Europe after the Bolshevik revolution, and Greece and Turkey exchanged parts of their populations after World War I.

Many displaced peoples were forced to resettle in the decades following World War II, creating even more intra-European migrations. Many ethnic Germans living in Central and Eastern Europe were expelled from their homes in retaliation for the war. While reliable numbers are hard to find, by the early 1950s almost 8 million ethnic Germans had moved into Western Germany, while some 3.5 million had moved into Eastern Germany. Also after the war, hundreds of thousands of southern Europeans emigrated to Northern Europe and the Americas to escape poverty and unemployment.

By the 1950s and 1960s, decolonization had resulted in people from Africa, the Middle East and Southeast Asia moving to their former colonial powers, creating demographic change in Europe. In many cases, European countries actually encouraged this movement, because immigrants were needed to bolster the workforce of a rapidly growing European economy.

But this golden era of the "guest workers" programs had one underlying issue: The policies were based on the assumption that the migrants would eventually return home. Most of these programs subsequently ended with the economic downturn that followed the oil crises of the early 1970s. However, migrants still continued to flow into Europe thanks to family reunification policies, Turkish families moving to Germany probably being the most distinct example.

The early 1990s were again a time of European migration, with Germany once more at the center of the process. The fall of the Berlin Wall enabled ethnic Germans living in Eastern Europe and the former Soviet Union to move to the reunified Germany, and people from the former East Germany move to the more developed West Germany. The 1990s were later marked by the collapse of Yugoslavia and the ethnic conflicts that followed, which forced even more people to seek Western Europe.

And in the 2000s, two events shaped migration to Europe. The first was the European Union's enlargement to the east, which allowed citizens from countries in the former Communist bloc to legally work in Western Europe. The second was the financial crisis, which encouraged hundreds of thousands of Portuguese, Spanish, Irish and Greeks to immigrate to Germany, the United Kingdom and other wealthy economies in the north.

Signs From the Past

The current migration flow into Europe is somewhat different from those of the past. Unlike the litany of previous population movements, this one involves a combination of asylum seekers from Syria, Iraq and Afghanistan and economic migrants from sub-Saharan Africa and the Balkans, most of whom arrive in Europe by land or sea. Many of these migrants endure long and dangerous trips from their countries of origin.