Seventy-two years after Anne Frank and her family were discovered and arrested in their Amsterdam hiding place, the plot of one of the Holocaust’s most tragic stories has thickened. Despite decades of suspicion that the family was betrayed, it turns out they may have instead have been found during an investigation for ration card fraud. The new theory sheds light not only on the fate of the Franks, but on the extent of Dutch resistance to the Nazis. Another way they resisted, writes Jeroen Dewulf, was through clandestine literature—a literature that, though little known today, illustrates just how Dutch people saw the German occupation.

“In no other country under German occupation during World War II was clandestine…literature more published than in the Netherlands,” writes Dewulf. These books and poems were highly illegal, but they sprang from a rich history of free-thinking on the part of the Dutch.

This history of free thought and expression was seen as intrinsically Dutch when the Germans occupied the country in 1940—so intrinsic that it became a rallying cry for Dutch people who felt their love of expression differentiated them from their oppressors. As a result, plenty of Dutch people flouted German authority, writing and publishing material that ran afoul of German cultural laws to works that outwardly challenged the Nazis.

The quality of these clandestine works was often poor, writes Dewulf. Conditions deteriorated throughout the war, and many of the Netherlands’ greatest minds were persecuted, imprisoned, or killed. But despite the instinct of many of the Netherlands’ librarians and publishers to censor themselves, some refused to stop publishing material critical of the Germans.

The occupation was accompanied by an aggressive Nazification campaign aimed at elevating Nazi ideals and rooting out cultural content that was deemed as subversive. Central to that campaign, writes Dewulf, was the so-called “Dutch Chamber of Culture,” an organization whose membership was compulsory for anyone who worked in the cultural sector. But many Dutch people refused to join or simply pretended they had stopped producing cultural works.

And yet underground publishing houses flourished. Some sold poems and books to raise money for Jewish children in hiding. Others used their proceeds to support Dutch artists who had to go underground because of their subversive opinions. Clandestine publishers circumvented rationing laws, producing miniature works so they would not run afoul of paper restrictions, and small print runs were common.

Overall, Dewulf estimates that there were over 1,000 clandestine items. “…one could say that clandestine literature represented the product that catered best to the main activity of the Dutch population: waiting,” writes Dewulf. He refers to Anne Frank’s documented excitement whenever a new piece of reading material entered her hiding place as an example of just how starved Dutch people were for entertainment and solace. But that solace came at a price for some. “At least 700 men and women of the underground press would lose their lives during the occupation,” writes Dewulf—an occupation that was both relieved and defied by the Netherlands’ brave underground artists.