On January 14, 1963, French President Charles de Gaulle caught everyone by surprise with a press conference in which he vetoed British entry into the Common Market and flatly ruled out French participation in a NATO multilateral force. Not knowing that de Gaulle and West German Chancellor Konrad Adenauer were just days away from springing another surprise–the Franco-German Treaty of 1963 (also known as the Élysée Treaty), former Secretary of State Dean Acheson telegrammed Adenauer directly, appealing to him to try to persuade de Gaulle to backtrack on the veto.