The Three Seas Initiative brings together twelve countries situated between the Black, the Baltic and the Adriatic Sea, i.e. Austria, Bulgaria, Croatia, the Czech Republic, Estonia, Lithuania, Latvia, Poland, Romania, Slovakia, Slovenia and Hungary. The idea behind the initiative is to develop a joint forum for closer co-operation between EU countries in Central Europe.

The history of the Three Seas countries is rich and the cultural and religious heritage of their nations diverse. However, the stories of those twelve countries have one common chapter that largely halted the economic growth of the region for almost fifty years. The Iron Curtain stretched from the Baltic to the Adriatic, dividing Europe into two parts and preventing international unity. While the nations of Western Europe were developing their infrastructure and became interconnected by roads, railways, power lines and oil and gas pipes, their Central and East European counterparts remained separated from one another, with outdated infrastructure and economic disparities. The deficit was particularly onerous in the north-south axis of the region. With the aid of the European Union, the situation has improved. Joint economic policy of the EU enabled stable growth of the whole of Europe; yet, economic inequalities that originated in the second half of the 20th century still persist. Eliminating that deficit would offer the region a fantastic development opportunity and make entire Europe stronger and more united.

In 2014, those inequalities were noticed by the Atlantic Council, the U.S. consultative organization. The issues described in their report inspired the President of Croatia Kolinda Grabar-Kitarović and the President of Poland Andrzej Duda to undertake in 2015 the economic and political initiative of the Three Seas aimed to boost cohesion initiatives undertaken by the European Union and complement them - without being a competitive project, as it is sometimes perceived.

Other major events in the history of the Three Seas Initiative were its Summits. So far, five such Summits have taken place:

• the first Summit of the Three Seas Initiative held on 25 August 2016 in Dubrovnik (Croatia). The participants adopted the declaration and expressed their approval for the Three Seas Initiative as the space for mutual support in economic projects.
• the second 3SI Summit held between 6 and 7 July 2017 in Warsaw, with Donald Trump as a special guest.
• the third 3SI Summit held between 17 and 18 September 2018 in Bucharest, Romania, during which the Three Seas Initiative Fund was established.
• the fourth 3SI Summit in Ljubljana, capital of Slovenia, held between 5 and 6 June 2019, during which formal registration of the Three Seas Initiative Investment Fund was officially confirmed.

Representatives of Czech, Romanian and Polish institutions joined the Fund authorities.

• the fifth 3SI Summit in Tallinn, Estonia held between 19 and 20 October 2020, at which the member states adopted the declaration of increased contribution to the Three Seas Fund. Due to the pandemic situation, the Tallinn Summit was held in the mixed formula, with in-person and remote participation.

Thus, the Three Seas initiative continues and its history is being written with each passing year. The next chapter will be the Local Government Economic Congress II Three Seas Initiative Forum of Regions coming up on 29th June 2021 in Lublin!