In response to President Raymond Poincaré's call for a Sacred Union on 4 August 1914, the French clergy played an active part in the war effort throughout the conflict, both on the front and behind the scenes, disseminating anti-German propaganda and encouraging the faithful to subscribe to the national loan. In application of the law of 15 July 1889, known as 'Les curés sac au dos' (Let the Priests Carry the Knapsack), 25,000 priests and seminarians were mobilised in 1914 and divided into three categories: combatants, clergy attached to the health service and military chaplains. The chaplains kept up soldiers' morale by celebrating mass and improving their living conditions (distributing cigarettes and postcards, etc.). We know about their everyday life from several sources, including the Lettres de prêtres aux armées edited by Victor Bucaille during the war, the Bulletin bimensuel des prêtres et des religieux mobilisés, published from 1915 to 1918, and paintings such as the Triptyque des Prêtres aux armées by Raymond Fournier-Sarlovèze. La Croix paid tribute to their involvement on 6 August 1914, 'There is nothing more consoling and comforting for the families who gave up their sons for the homeland than the thought that there is a priest on the battlefield.'