1st May 2004 – The 'Big Bang' Enlargement of the European Union

Pictured: Enlargement ceremony in 2004 celebrating the EU10 joining the EU in May 2004 in Dublin, Ireland.

The 1st May 2004 was the day that 10 European countries, consisting of Czechia, Estonia, Cyprus, Latvia, Lithuania, Hungary, Malta, Poland, Slovenia and Slovakia ('EU10') joined the European Union (EU). Of these 10, 8 were former Eastern-Bloc nations, signifying a beginning of the end to the division of European countries based on the borders set during the Cold War.

Overnight, the population of the EU increased by over 74 million, from 385 million to 459 million; the largest increase in population from enlargement to date. Since 2000, trade exchange between the EU countries prior to 2004 and the EU10 has increased five-fold, as the income gap between these two groups of countries has narrowed significantly. Since 2004, the EU10 have experienced GDP growth greater than the EU average consistently.

Pictured: A map with the countries that joined the EU in 2004 shown in yellow. EU member states that had joined previously are shown in blue.

To join the EU all 10 countries had to comply with Article 6 of the EU, which states that any member state must uphold:

"The principles of freedom, democracy, respect for human rights and fundamental freedoms and the rule of law."

In addition, the EU10 also had to pass the Copenhagen Criteria:

• Be a stable democracy, respecting human rights, the rule of law and protecting minorities.

• Have a working market economy.

• Adopt the common rules, standards and policies which make up EU law.

As part of the process, the EU had to adapt to the now much-larger EU, including expanding its language services. The countries already part of the EU also had to contribute more of their EU budget towards these new member states, meanwhile the EU10 countries had to conduct major reforms in order to meet the criteria required for joining.

Nowadays, many of the EU10 countries, particularly Poland, are now integral members of the EU, with both economic and political influence in the EU. Many of the EU10 have been the most critical members of the EU on its response to the Russo-Ukrainian War, advocating for more support to Ukraine, based on the shared experiences of many of these countries under USSR rule and a desire to see Ukraine potentially join the EU and become a prosperous member, in a similar manner to the EU10 who joined 21 years ago.

Pictured: A commemorative €100 coin from Belgium celebrating the enlargement.

This enlargement is perceived in general to have been very successful, helping improve living standards in the former Eastern Bloc, whilst continuing the European peace project by expanding it to countries that merely 13 years prior were on either side of the Cold War.