The authors of the contribution focused on diaries and recollections of the Austrian-Hungarian troops members, captured at different fronts in World War I (in Serbia, Russia, and Italy), who later joined the Czechoslovak volunteer armed forces - the Czechoslovak legions. On an example of recorded memories of French legionnaire A. Sima, Italian legionnaire V. Valnicek and Russian legionnaire A. Sikura, the authors explain the circumstances at the time when World War I broke out, the moods and opinions of inhabitants, the mobilisation and leaving for the front, the baptism of fire at the fronts, the trials and horrors of war. Their diaries demonstrate clearly, how they as private soldiers and the civil inhabitants experienced the apocalyptic moments brought by the worldwide conflict to the proximity of the fronts and the rear, their everyday life and the importance of the memories of their relatives at home and of the rare correspondence with them. As immediate witnesses of significant political and military events from 1914-1918, when the future fate of Czechs and Slovaks and their common state - the Czechoslovak Republic - was decided, they provide a conclusive picture of those difficult times. Their records from war years, which were completed and even printed later, helped to keep the essential and even less essential experiences from that period in individual mind of their relatives and in collective mind of the nation. Frequently, they give also the historians, military historians, ethnologists and other experts very detailed and from other sources unknown information.