Mignano Montelungo Battle stands out as the first episode of frontal clash between the Allied armies and the Wehrmacht that occurred along the defence lines related to the Gustav Line drawn in central-southern Italy, during the first phase of the campaign for the country's liberation.

The wartime event that took place between 8 and 16 December 1943, assumes an even more intense importance in the Italian collective memory as it was the first battle undertaken by the reorganised Italian troops following the armistice with the Allied powers and as part of the new co-belligerence strategy. In fact, the first battalions of the reconstituted Army of the Southern Kingdom arrived on the heights of Monte Lungo from 7 December in support of the US troops, joined within a newly formed military formation: the 1st Motorised Regiment. Under the leadership of General Vincenzo D'Apino, the Italian troops were deployed for the first time on the front line right on the heights of Monte Lungo, attempting to break through the Bernhardt Line, a straggler line of the Gustav Line.

During the first battle of 8 December, notwithstanding the massive effort and will to rout the Nazi positions, because of incomplete information about the enemy's size and positioning and left exposed by the sudden thinning of the fog, the Italian troops suffered a severe German counter-offensive that resulted in the failure of the operation. Despite huge casualties, the soldiers of the First Motorised Regiment did not give up and re-organised themselves and launched a new onslaught on 16 December. The Allies succeeded this time in inflicting a considerable defeat on the Nazi troops, who were forced to abandon their positions, leaving the Italian tricolour and the US flag flying on the peaks of Monte Lungo.

The achievement of the First Motorised Regiment in terms of war effort and the sacrifice of human lives, at Mignano Monte Lungo, allowed the reconstituted Italian army to continue its collaboration with the Allies for the nation's liberation from the occupying forces. A fundamental first milestone that paved the way on the lines to freedom.