The origin of this body is found in the Congregatio super negotiis ecclesiasticis extraordinariis Regni Galliarum (Congregation on the Extraordinary Ecclesiastical Affairs of the Kingdom of France) that Pope Pius VI set up on 28 May 1793 to deal with problems arising for the Church as a result of the French Revolution.
[1] This arrangement was incorporated into the 1917 Code of Canon Law, which described the Secretariat of State as composed of three sections, of which this congregation was the first: In its canon 255, that Code defined the congregation's field of competence as erecting or dividing dioceses and appointing bishops where negotiations with civil governments were involved, and other matters that the Pope might choose to entrust to it, especially those in some linked to civil law and the Holy See's agreements and concordats with states.
He established what had been the First Section as a body distinct from the Secretariat of State, though closely related, and called it the Council for the Public Affairs of the Church.
[1] Articles 45–47 of Pastor Bonus indicate dealing with heads of government as the special task of the Section for Relations with States.
Its field of competence includes fostering diplomatic and other relations with states and other subjects of public international law such as the United Nations and the European Union, dealing with matters of common interest to them and to the Holy See by means such as concordats and similar agreements, while respecting the views of interested episcopal conferences.