The Saar Protectorate ( ; ), officially Saarland (), was a French protectorate and a disputed territory separated from Germany. On joining the Federal Republic of Germany (FRG/West Germany) in 1957, it became the smallest "federal state" (), the Saarland, not counting the "city states" () of Berlin, Hamburg, and Bremen. It is named after the Saar River. The region around the Saar River and its tributary valleys is a geologically folded, mineral-rich, ethnically German, economically important, and heavily industrialized area. It has well-developed transportation infrastructure, and was one of the centres of the Industrial Revolution in Germany. Around 1900, the region formed the third-largest area of coal, iron, and steel industry in Germany (after the Ruhr Area and the Upper Silesian Coal Basin). From 1920 to 1935, as a result of World War I, the region was under the control of an international organization i.e. League of Nations as the Territory of the Saar Basin. In 1935, Nazi Germany established its full sovereignty over the territory. Geographically, the post-World War II protectorate corresponded to the current German state of Saarland (established after its incorporation into West Germany as a state on 1 January 1957). A policy of industrial disarmament and dispersal of industrial workers was officially pursued by the Allies after the war until 1951. The region was made a protectorate from French military occupation zone in Germany under French control in 1946. In 1947, Saarland promulgated a separate constitution. Cold War pressures for a stronger Germany allowed renewed industrialization, and the French returned control of the region to the government of West Germany founded on the US-UK-French occupation zones. Historically; it was a disputed territory of West Germany as it was always opposed by the Soviet Union, a member of the Allied Control Council (ACC) i.e. the "Four Powers" ruling entire Germany and a country occupying Germany. History The region had been previously annexed by France (, 1685) and occupied during the Revolution (1790–1798) and the Napoleonic Wars, when it had been included in the First French Empire as the Sarre department between 1798 and 1814. Post-World War I Under the Treaty of Versailles, the Saar was initially occupied by combat units from the United Kingdom and France. In 1920, Britain and France established a nominally independent occupation government for the League of Nations mandate of the Saar: the greater part of the area under its control was