This essay tells the story of the German POW-camp Halbmondlager (eng. Crescent Moon Camp), and explores why the leadership’s goal of radicalizing the Muslim POWs was unsuccessful. Halbmondlager was located in Wünsdorf, an hour away from Berlin, and active during World War I. Inside the walls of the camp, the goal was to turn the ca. 3000 Muslim POWs ­­– that had previously fought in the French and English armies ­– into Jihadists, prepared to fight in an holy war for Germany against the French-English alliance. In retrospect, the project was admittedly a failure. In the first part of the essay’s analysis, I give a description of the camp environment, put together through qualitative text analysis of archive material collected at the Political Archive at the Foreign Office in Berlin. In the second part of the analysis, I explore why the radicalization project failed, by analyzing the camp and its environment through modern relational radicalization theory, and the leadership’s thoughts on Islam. My conclusion is that the relational radicalization theory exposes more than one reason as to why the POWs did not become radicalized, but that it is also necessary to keep the then dominant thoughts of Islam as a religion connected to war in mind to get a full picture of why the project failed.