The first traces of human civilization in Geneva, discovered on the shores of Lake Léman, date from around 3000 BC. The hill of the Old City, however, was not inhabited until 1000 BC. Later, when Rome conquered Geneva, it was defended by a small Celtic tribe. In 58 BC, Julius Caesar drove off an attack by the Helvetii. At the height of the Roman Empire, around 400 AD, it became a bishopric.
The region was settled in 443 by a Germanic tribe, the Burgundians, but they were defeated later by the Francs, who occupied it in 534. Geneva was incorporated into the Merovingian dynasty, then into the Carlovingian Empire. The latter's disintegration in the 11th century led to the rise of the Second Burgundian Kingdom, to which Geneva belonged. In 1032, the kingdom passed into the hands of the Germanic emperors so Geneva legally became subject to the Empire. In practice, though, from the 11th century to the Reformation, it was ruled by its bishops, who had become the de facto lords of the city.
Geneva did not develop into an important centre until the end of the Middle Ages when its fairs, reaching their peak in the 15th century, first gave it an international reputation. Its independence, however, was threatened by Savoy, whose princes strove unsuccessfully from the 13th to the 17th century to force the town into submission. At its time of gravest danger, during the first third of the 16th century, the city' autonomy was saved by the intervention or the Swiss cantons of Fribourg and Bern. When the Reformation triumphed in 1535, the city became a republic. Calvin made Geneva his home the following year, and it was through his genius that the city earned the name "Protestant Rome". From 1550 onwards, persecuted Protestants, mainly French and Italians, streamed into Geneva in search of sanctuary. Under the guidance of Calvin and Théodore de Bèze, they gave their new home a greater religious and intellectual influence.
The refugees also helped to redress the economy, which had been in recession since the fairs had gone into decline at the end of the preceding century. In 1602, the Duke of Savoy, Charles Emmanuel, launched an abortive nighttime attack against Geneva, which has come to be known as the "Escalade" (literally, "scaling the walls"). The festival commemorating it on December 11-12 is Geneva's main patriotic celebration. A second wave of refugees flooded into Geneva at the end of the 17th century following Louis XIV's savage persecution of Protestants in France. The 18th century was a period of enormous prosperity when industries - horology is the best known - business and banking flourished. Rousseau was born in Geneva in 1712 and Voltaire lived there from 1775 to 1778. On the other hand, Geneva was shaken by political and social agitation.
The Geneva revolution of 1792 brought down the aristocratic government of the Ancien Régime and proclaimed political equality. Geneva was annexed by France in 1798 and made the administrative centre of the Department of Léman. Its freedom was restored on December 31, 1813, following the defeat of Napoleon's armies. The republic's magistrates then applied for its entry into the Swiss Confederation. This was granted in 1815. A revolution in 1846 led by James Fazy overthrew the government of the Restoration and established the constitution that is still in force in the canton today. During the 19th century and at the beginning of the 20th, Geneva welcomed many political refugees. Based on the ideas expressed by the Genevan, Henri Dunant, the International Committee of the Red Cross was founded in 1864, the first of many international organizations to settle there.
Geneva's international role was confirmed after the First World War when it was chosen as the site for the headquarters of the League of Nations, the forerunner of the United Nations Organisation.