The First World War led to a fundamental reorganization of international relations. This had a profound impact on churches and mission agencies and their ecumenical networks. European Christianity was increasingly questioned. The shock was all the greater since the war alliances were formed without taking religious orientation into consideration. This volume examines the impact of the war on church and mission especially in Africa and Asia. The contributions provide a wide scope of historical analyses with a focus on the Hermannsburg Mission. The symposium was organized by the Ludwig-Harms-Kuratorium and the Fachhochschule für Interkulturelle Theologie Hermannsburg in 2018.