Wren was a highly secretive man, and his service in the Legion has never been confirmed. When his novels became famous, there was a mysterious absence of authenticating photographs of him as a legionnaire or of the usual press-articles by old comrades wanting to cash in on their memories of a celebrated figure. It is now thought more likely that he encountered legionnaires during travels in French North Africa, and skillfully blended their stories with his own memories of a short spell as a cavalry trooper in Britain. While his fictional accounts of life in the pre-1914 Foreign Legion are highly romanticised, his details of Legion uniforms, training, equipment and barrack room layout are generally accurate. This may, however, simply reflect careful research on his part. The descriptions of Legion garrison life given in his work "The Wages of Virtue", published in 1916, closely match those contained in the autobiographical "In the Foreign Legion" by ex-legionnaire Edwin Rosen, published by Duckworth London 1910.