By March 1915, Max Aitken--a millionaire press baron with connections to Robert Borden and Sam Hughes--was allowed to make reports from the front as Canada's "Eyewitness to War." In January 1916, Aitken formally established the Canadian War Records Office (CWRO).
All were established British press photographers who were integrated into the military ranks, producing thousands of shots for the CWRO. Castle went on to produce some of the most infamous shots of the war.
The photographs allow historians to ask questions of the CWRO's system of Information: How were official photographers hired?