For centuries, the tiny Alpine nation of Switzerland has adhered to a policy of armed neutrality in global affairs. Switzerland isn’t the world’s only neutral country—the likes of Ireland, Austria and Costa Rica all take similar non-interventionist stances—yet it remains the oldest and most respected. How did it earn its unique place in world politics?

The earliest moves toward Swiss neutrality date to 1515, when the Swiss Confederacy suffered a devastating loss to the French at the Battle of Marignano. Following the defeat, the Confederacy abandoned its expansionist policies and looked to avoid future conflict in the interest of self-preservation.

It was the Napoleonic Wars, however, that truly sealed Switzerland’s place as a neutral nation. Switzerland was invaded by France in 1798 and later made a satellite of Napoleon Bonaparte’s empire, forcing it to compromise its neutrality. But after Napoleon’s defeat at Waterloo, the major European powers concluded that a neutral Switzerland would serve as a valuable buffer zone between France and Austria and contribute to stability in the region. During 1815’s Congress of Vienna, they signed a declaration affirming Switzerland’s “perpetual neutrality” within the international community.

Switzerland maintained its impartial stance through World War I, when it mobilized its army and accepted refugees but also refused to take sides militarily. In 1920, meanwhile, the newly formed League of Nations officially recognized Swiss neutrality and established its headquarters in Geneva. A more significant challenge to Swiss neutrality came during World War II, when the country found itself encircled by the Axis powers. While Switzerland maintained its independence by promising retaliation in the event of an invasion, it continued to trade with Nazi Germany, a decision that later proved controversial after the war ended.

Since World War II, Switzerland has taken a more active role in international affairs by aiding with humanitarian initiatives, but it remains fiercely neutral with regard to military affairs. It has never joined the North Atlantic Treaty Organization (NATO) or the European Union, and only joined the United Nations in 2002. Despite its longstanding neutrality, the country still maintains an army for defense purposes and requires part-time military service from all males between the ages of 18 and 34.