The organization was formed in 2001 by a group of historians and journalists with the aim of increasing public knowledge of the 20th century history of the Czech Republic and neighboring countries, especially among younger generations.

[1]: 2 [2] Post Bellum has collected thousands of witness accounts by conducting interviews with people who lived through significant periods in history as part of their documentation project, Stories of the 20th Century, and for their online archive, Memory of Nations.

The organisation has created an archive of oral historical testimony entitled Memory of Nations, in partnership with the Institute for the Study of Totalitarian Regimes and Czech Radio.

[1]: 4  The archive is the largest online collection of testimonies in Central Europe, documenting the stories of "war veterans, Holocaust survivors, political prisoners, as well as members of the Communist Party, the Secret Police, and the People’s Militias".

Post Bellum also developed an app, Memory of Nations Sites, with an interactive map allowing users to access archive materials from the 20th century related to their current location.

In November 2014, the award was presented to people involved in resistance to the Iron Curtain in the Czech Republic, Slovakia, Hungary, Poland and Germany, to commemorate the 25th anniversary of the fall of communism in Europe.

Post Bellum has also published a number of educational books such as We Are Still At War and Forced Labour, graphic novels based on true stories of people affected by totalitarian regimes.

The exhibition immerses visitors in World War II alongside two witnesses, Jaryna Mlchová and Tomáš Sedláček, and also includes three themed workshops: "Jews in the Protectorate," "The Second Resistance," and "Political Prisoners.

Post Bellum held 47 public events at the institute's city-center location at Radnická 10, including discussions featuring war veteran Roman Kopřiva, author Pavel Kosatík, and historian Denisa Nečasová.