Foreign policy co-operation between member states dates from the establishment of the Community in 1957, when member states negotiated as a bloc in international trade negotiations under the EU’s common commercial policy. Steps for a more wide-ranging co-ordination in foreign relations began in 1970 with the establishment of European Political Cooperation which created an informal consultation process between member states with the aim of forming common foreign policies. In 1987 the European Political Cooperation was introduced on a formal basis by the Single European Act. EPC was renamed as the Common Foreign and Security Policy (CFSP) by the Maastricht Treaty.

The aims of the CFSP are to promote both the EU’s own interests and those of the international community as a whole, including the furtherance of international co-operation, respect for human rights, democracy, and the rule of law. The CFSP requires unanimity among the member states on the appropriate policy to follow on any particular issue. The unanimity and difficult issues treated under the CFSP sometimes lead to disagreements, such as those which occurred over the war in Iraq.

The coordinator and representative of the CFSP within the EU is the High Representative of the Union for Foreign Affairs and Security Policy who speaks on behalf of the EU in foreign policy and defence matters, and has the task of articulating the positions expressed by the member states on these fields of policy into a common alignment. The High Representative heads up the European External Action Service (EEAS), a unique EU department that has been officially implemented and operational since 1 December 2010 on the occasion of the first anniversary of the entry into force of the Treaty of Lisbon. The EEAS will serve as a foreign ministry and diplomatic corps for the European Union.

Source

https://en.wikipedia.org/wiki/European_Union#Foreign_relations (23.12.2019)