Italians in Germany consist of ethnic Italian migrants to Germany and their descendants, both those originating from Italy as well as from among the communities of Italians in Switzerland. Most Italians moved to Germany for reasons of work, others for personal relations, study, or political reasons. Today, Italians in Germany form one of the largest Italian diasporas in the world and account for one of the largest immigrant groups in Germany. It is not clear how many people in Germany are of Italian descent, since the German government does not collect data on ethnicity. However, based on the German "microcensus," which surveys 1% of the German population annually and includes a question on the nationality of the surveyees' parents, the number is at least 873,000 people. The total number (i.e. including third generation Italian Germans and beyond) is likely considerably higher. History Pre-unification (to 1871) Large numbers of Italians have resided in Germany since the early Middle Ages, particularly architects, craftsmen and traders. During the late Middle Ages and early modern times many Italians came to Germany for business, and relations between the two countries prospered. The political borders were also somewhat intertwined under the German princes' attempts to extend control over all the Holy Roman Empire, which extended from northern Germany down to Northern Italy. During the Renaissance many Italian bankers, architects and artists moved to Germany and successfully integrated in the German society. German unification to end of World War II (1871–1945) Germany was a comparatively minor destination of Italians during the waves of Italian emigration after Italian unification and the resulting breakdown of the feudal system, with most leaving for the Americas. Between 1876, the year Italy began keeping track of people leaving the country permanently, and 1915, around 1.2 million Italians moved to Germany. For comparison, a total of 14 million Italians emigrated to various parts of the world during this period. Post-World War II (1945–1990) With Germany's post-World War II economic boom (Wirtschaftswunder), the country signed a number of immigration treaties with other mostly European nations starting in 1955 with Italy, which allowed immigrants to move to Germany in large numbers to work and live. The treaty allowed companies experiencing labor shortages to request the transference of Italian workers via the Italian Ministry of Labor. Italy had signed a number of such treaties with other countries in Europe, Oceania and South America in the 1950s