Formed in 1991 in the  Hungarian town of the same name, the Visegrad Group is the regional alliance of four closely linked Central European countries.

"The Czech Republic, Hungary, Poland and Slovakia have always been part of a single civilization, sharing cultural and intellectual values and common roots in diverse religious traditions, which they wish to preserve and further strengthen" is the description of the Visegrad Group, also known as V4, on the alliance's website.

Read more: Slovakia eyes kingpin Visegrad role amid EU tensions

The V4 countries, once satellite states of the Soviet Union, all became EU members on May 1, 2004. Austria — which borders the Czech Republic, Hungary and Slovakia — has shown an interest in joining the group.

'Encouraging optimum cooperation'

The countries do not "try to compete with the existing functional Central European structures," according to the V4. Instead, the group works toward "encouraging optimum cooperation with all countries, in particular its neighbors, its ultimate interest being the democratic development in all parts of Europe."

In 2000, the group created the International Visegrad Fund to support scholarships, grants, and cooperation in the areas of culture, scientific exchange, research, education and the promotion of tourism. The fund also financially supports the Think Visegard network, which was created in 2012 by eight V4 research centers and institutes.

Poland has the region's largest economy, followed by the Czech Republic, Hungary and Slovakia — the only Visegrad country to have adopted the euro as its official currency. 

Similarities and disputes

The countries differ on many issues, a major one being how closely to partner with Russia, but they have embraced similar migration policies. V4 leaders oppose the refugee quotas endorsed by many other EU member states.

The euroskeptic government in Poland refuses to accept refugees, and billionaire businessman Andrej Babis, whose party won the most votes in the 2017 parliamentary elections in the Czech Republic, has pledged to keep the borders closed to refugees. In Hungary, Prime Minister Victor Orban seeks to preserve "ethnic homogeneity." Slovakia is the only Visegrad state currently ruled by a Social Democrat, but even the nominally centrist Robert Fico has attempted to connect terrorism to refugees and religion. 

They also tend to oppose deferring to the EU on issues that they consider domestic policy. Poland and Hungary in particular have clashed with the European Commission, much more so than Slovakia and the Czech Republic.

The V4 cooperates with other regional blocs, such as Benelux Union and the Nordic Council of Ministers.