France–Germany relations of the further integration of the EU. They are sometimes described as the "twin engine" or "core countries" pushing for moves. A tram straddling the Franco-German border, across the river Rhine from Strasbourg to Kehl, was inaugurated on the 28th of April 2017 symbolising the strength of relation between the two countries. Both France and Germany track their history back to the time of Charlemagne, whose vast empire included most of the area of both modern-day France and Germany – as well as the Netherlands, Belgium, Luxembourg, Switzerland, Austria, Slovenia, and northern Italy. The death of Charlemagne's son Louis the
Belgium in World War I Belgium also received a small slice of territory in the east of the country (known as Eupen-Malmedy) from Germany, which remains part of the country to this day. Its demands for a slice of Zeeland in the Netherlands (which had remained neutral during the conflict), were rejected and led to ill-will. Britain was willing to guarantee Belgian borders only if it committed to neutrality, which Albert rejected. Instead, Belgium became a junior partner with France in an occupation of part of Germany under a 1920 Treaty. As outlined in the Treaty of Versailles, Belgium was also given a League of