It was 1866, during the Austro-Prussian War. The Principality of Liechtenstein was then part of the German Confederation (which would later become Germany).
The Prince of Liechtenstein sent 80 soldiers to guard a pass in the Alps, on the border with Austria, in case of a possible attack. But there was no fighting there, and the war soon ended.
Afterward, the Liechtenstein army marched home in victory, where they were greeted with a triumphant welcome by the locals. However, instead of 80 men, only 81 returned.
There is no precise information about the identity of the soldiers' new friend. However, according to some sources, it was an Italian farmer whom the army encountered on their way home.