In the summer of 1866, the Austro-Prussian War broke out, a conflict that redefined the balance of power in Central Europe. As a loyal member of the German Confederation, the tiny Alpine principality of Liechtenstein sided with the Austrian Empire and mobilized its entire military contingent: a battalion of just 80 soldiers.
Their mission was to guard the strategic Brenner Pass, on the mountainous border between Austria and Italy. Weeks went by in absolute Alpine tranquility; the Italian contingent never advanced toward their sector, and the troops from Liechtenstein spent their days patrolling in the sun, drinking local wine, and enjoying the scenery without needing to fire a single shot.
When the conflict ended barely seven weeks later, the soldiers set off on their way back home. Upon arriving in the capital, Vaduz, and taking the official roll call on August 22, 1866, the officers discovered a fascinating mathematical anomaly: 80 men departed, but 81 returned.
According to historical records, during their stay at the border they had befriended an Italian liaison officer—or according to other sources, an Austrian deserter—who decided to join the group, fascinated by the unit's camaraderie, and accompany them back to their country.
Grateful for the peaceful outcome, Prince Johann II disbanded the Liechtenstein army in 1868 citing unnecessary expense, establishing the country as one of the few nations on the planet without a standing military.
Source: Historisches Lexikon des Fürstentums Liechtenstein (HLFL)
