Zwei-plus-Vier-Vertrag
On 15 March 1991, the Treaty on the Final Settlement with Respect to Germany—that had been signed in Moscow back on 12 September 1990 by the two German states that then existed (East and West Germany) on one side, and by the four principal Allied powers (the United Kingdom, France, the Soviet Union and the United States) on the other—entered into force, having been ratified by the Federal Republic of Germany (after the unification, as the united Germany) and by the four Allied nations. The entry into force of that treaty (also known as the "Two Plus Four Treaty", in reference to the two German states and four Allied nations that signed it) put an end to the then-remaining limitations on German sovereignty that resulted from the post-World War II arrangements.