Why did they refer to it as “post great war”? What war are they referring to? How did that impact the music?

War is a terrible thing. Yet the cadence of troops marching through the streets, the ringing sound of national airs, the flapping of proudly hoisted flags, and, in more modern times, the swoosh of aircraft racing overhead typically send hearts pounding and aspirations soaring. Inevitably, it is in the period following the cessation of hostilities, in times of so-called peace, that the initially envisioned mission becomes increasingly difficult to identify. An awareness of the cohorts of war surfaces even more gradually, and only in recent decades has the study of the Great War of 1914–1918 moved beyond politics.