Originally inhabited by the Helvetians, or Helvetic Celts, the territory comprising modern Switzerland came under Roman rule during the Gallic wars in the 1st century BC and remained a Roman province until the 4th century AD. Under Roman influence, the population reached a high level of civilization and enjoyed a flourishing commerce. Important cities, such as Geneva, Basel, and Zurich, were linked by military roads that also served as trade arteries between Rome and the northern tribes.

After the decline of the Roman Empire, Switzerland was invaded by Germanic tribes from the north and west. Some tribes, such as the Alemanni in central and northeastern Switzerland, and the Burgundians, who ruled western Switzerland, settled there. In 800, the country became part of Charlemagne’s empire. It later passed under the dominion of the Holy Roman emperors in the form of small ecclesiastic and temporal holdings subject to imperial sovereignty.

With the opening of a new important north-south trade route across the Alps in the early 13th century, the Empire’s rulers began to attach more importance to the remote Swiss mountain valleys, which were granted some degree of autonomy under direct imperial rule. Fearful of the popular disturbances flaring up following the death of the Holy Roman Emperor in 1291, the ruling families from Uri, Schwyz, and Unterwalden signed a charter to keep public peace and pledging mutual support in upholding autonomous administrative and judicial rule. The anniversary of the charter’s signature (August 1, 1291) today is celebrated as Switzerland’s National Day.

Between 1315 and 1388 the Swiss Confederates inflicted three crushing defeats on the Habsburgs, whose aspiration to regional dominion clashed with Swiss self-determination. During that period, five other localities (cantons in modern-day parlance) joined the original three in the Swiss Confederation. Buoyed by their feats, the Swiss Confederates continuously expanded their borders by military means and gained formal independence from the Holy Roman Empire in 1499. Routed by the French and Venetians near Milan in 1515, they renounced expansionist policies. By then the Swiss Confederation had become a union of 13 localities with a regularly convening diet administering the subject territories. Swiss mercenaries continued for centuries to serve in other armies; the Swiss Guard of the Pope is a vestige of this tradition.

The Reformation led to a division between the Protestant followers of Zwingli and Calvin in the German and French parts of the country respectively, and the Catholics. Despite two centuries of civil strife, the common interest in the joint subject territories kept the Swiss Confederation from falling apart. The traffic in mercenaries as well as the alienation between the predominantly Protestant Swiss and their Catholic neighbors kept the Swiss Confederation out of the wars of the European powers, which formally recognized Swiss neutrality in the Treaty of Westphalia in 1648. The Swiss remained neutral during the War of the First Coalition against revolutionary France, but Napoleon, nonetheless, invaded and annexed much of the country in 1797-98, replacing the loose confederation with a centrally governed unitary state.

The Congress of Vienna in 1815 re-established the old confederation of sovereign states and enshrined Switzerland’s status of permanent armed neutrality in international law. In 1848, after a brief civil war between Protestant liberals seeking a centralized national state and Catholic conservatives clinging on to the old order, the majority of Swiss Cantons opted for a Federal State, modeled in part on the U.S. Constitution. The Swiss Constitution established a range of civic liberties and made far-reaching provisions to maintain cantonal autonomy to placate the vanquished Catholic minority. The Swiss amended their Constitution extensively in 1874, establishing federal responsibility for defense, trade, and legal matters, as well as introducing direct democracy by popular referendum. To this day, cantonal autonomy and referendum democracy remain trademarks of the Swiss polity.

Switzerland industrialized rapidly during the 19th century and by 1850 had become the second most industrialized country in Europe after Great Britain. During World War I serious tension developed between the German, French, and Italian-speaking parts of the country, and Switzerland came close to violating its neutrality but managed to stay out of hostilities. Labor unrest culminating in a general strike in 1918 marked the interwar period, but in 1937 employers and the largest trade union concluded a formal agreement to settle disputes peacefully, which governs workplace relations to the present day. During World War II, Switzerland came under heavy pressure from the fascist powers, which after the fall of France in 1940 completely surrounded the country. Some political and economic leaders displayed a mood of appeasement, but a combination of tactical accommodation and demonstrative readiness to defend the country helped Switzerland survive unscathed.

The Cold War enhanced the role of neutral Switzerland and offered the country a way out of its diplomatic isolation after World War II. Economically, Switzerland integrated itself into the American-led Western postwar order, but it remained reluctant to enter supranational bodies. Switzerland did not join the United Nations, even though Geneva became host to the UN’s European headquarters, and the country played an active role in many of the UN’s specialized agencies. Switzerland also remained aloof in the face of European integration efforts, waiting until 1963 to join the Council of Europe. It still remains outside the European Union. Instead, Switzerland in 1960 helped form the European Free Trade Area, which did not strive for political union. Following the Cold War, Switzerland joined the Bretton Woods institutions in 1992 and finally became a member of the United Nations in 2002.