A young conservative, Arne Sejr, wrote 'Danskerens Regler' (The Rules of the Dane) on the very day of the invasion, and instigated civil disobedience and sabotage of Nazi rule. As the war went on, thousands of members of KU began committing illegal sabotage, writing illegal papers and employing guerilla tactics. Typically the recruitment of freedom fighters took place in 'terrænsportsforeninger' (terrain sports clubs) which were legal gymnastics clubs that arranged orienteering, but also functioned as a cover for recruitment and training camps, employing military-like training exercises.