diff --git a/3-4_marches/on_the_road_to_passchendaele/config.ily b/3-4_marches/on_the_road_to_passchendaele/config.ily
index e652ee9..90fd975 100644
--- a/3-4_marches/on_the_road_to_passchendaele/config.ily
+++ b/3-4_marches/on_the_road_to_passchendaele/config.ily
@@ -2,6 +2,7 @@
 %% Globals
 global = {
 	\time 3/4
+	\key a \mixolydian
 	}
 confTempo = {
 	\tempo 4 = 78