Zwei-plus-Vier-Vertrag
With German reunification finally within reach in 1990, the Allies of World War II made full sovereignty for Germany conditional on the final recognition of the Oder–Neisse border, as stipulated in article 1.2 of the Treaty on the Final Settlement with Respect to Germany. The signing of a treaty between Germany and Poland recognizing the Oder–Neisse line as the border under international law was also one of the terms of the Unification Treaty between West and East Germany that was signed and went into effect on 3 October 1990. Poland also wanted this treaty to end the ambiguity that had surrounded the border issue since 1945.