Although the national conflict from the pre-World War I period had cooled down, the economically powerful German minority were not satisfied with their position in Celje.
Political scene that involved a clash of ideologies pushing for a new division of the world painted a bleak outlook years before the outbreak of the global cataclysm. Reports of occupation by the Nazi army of some countries of the Western Europe on the one hand, and the communist Soviet Union of a part of Eastern Europe on the other hand, only reinforced the premonitions of war. The invasion of Yugoslavia on April 6, 1941, was the start of four long torturous years for the small Slovenian nation, numbered at 1.5 million at the time. The bottom line of the war was terrifying. Celje alone, with a population of 20,000, and its broader area, lost 575 people, mostly aged between 20 and 30. Over 1,500 people were deported to Serbia or the central parts of the German Reich; approximately 300 were interned, around 1,000 were incarcerated in the Celje prisons, and an unknown number of Celje residents were forcibly recruited to the German army. The children were not spared either. Around 600 "stolen children" were taken to Germany for so-called Germanization.
Sadly, the time after the war would not bring freedom for all either. As a part of Yugoslavia, Slovenia went from one totalitarianism to another. Extremists of the victories Communist Party took cruel revenge on their adversaries. Many Slovenians who collaborated more or less closely with the occupiers as members of the quisling units died in the Teharje camp a few kilometres from Celje. Estimates put the number of Slovenians killed hastily and without due trial in the aftermath of World War II at around 12,000. The wounds of Teharje run deep and have not healed to this day.