Roman rule had ceased by 508, when Clovis the Frank made the city the capital of the Merovingian dynasty of the Franks. Viking invasions during the 800s forced the Parisians to build a fortress on the Ile de la Cité. On March 28, 845 Paris was sacked by Viking raiders, probably under Ragnar Lodbrok, who collected a huge ransom in exchange for leaving.
Less positively and very controversially, the ancient market at Les Halles was demolished and replaced with a notoriously ugly underground shopping mall, and the 209m Tour Montparnasse skyscraper was built leading to fears that Paris would become overrun with American-style skyscrapers (a move strongly resisted ever since).
France's political divisions were a major factor in its ill-preparedness for the outbreak of the Second World War on 3 September 1939. Some of the Catholic Right were openly hostile to parliamentary democracy, Socialism and Communism, and welcomed the possibility of a fascist regime, even imposed by foreign forces.
With other European powers mobilising to crush the Revolution, which they saw as threatening their own monarchies, the political climate in Paris worsened as rumours of foreign plots and invasions took hold.
The revolutionaries became steadily more extreme, turning on the "enemy within." This included not just royalists but those accused of simply being not sufficiently revolutionary, including Danton and Camille Desmoulins. Over 1,300 people were executed in just six weeks in 1794. In the end, the extremists' bloodthirstiness destroyed their own moral standing; a group of moderates seized control in July 1794, sending Robespierre and his allies to the guillotine in a last spasm of bloodletting.
The victor was, to the surprise of many, Louis-Napoleon Bonaparte - the nephew of the late Emperor. He won by an overwhelming majority (receiving 75% of the votes cast) but was not content with being a mere president. On 2 December 1851 he seized power in a coup, declared himself the Emperor Napoleon III and settled in the Tuileries Palace.
Roman rule in northern Gaul effectively collapsed in the 5th century. In 451 the region was invaded by Attila the Hun, prompting fears that Paris would be attacked. According to legend, the city was saved by the piety of Sainte Geneviève and her followers, whose prayers for relief were answered when Attila's march turned away from Paris to the south. Ste Geneviève remains Paris' patron saint to this day.
His grandson Louis IX, renowned for his extreme piety (and later canonised as St Louis) established the city as a major centre of pilgrimage in the 13th century with the construction of the cathedral of Notre Dame de Paris, the Basilica of St Denis and the Sainte-Chapelle on the Ile de la Cité. The latter was one of the finest medieval Gothic religious buildings ever constructed and was built to house Louis' most precious possession - the (alleged) Crown of Thorns, purchased from the bankrupt Byzantine Empire at an extortionate price.
Matters came to a head on 23 August 1572 with the St Bartholomew's Day Massacre, when Catholic mobs killed an estimated 3,000 Protestants on the instructions of King Charles VIII. His successor, King Henry III, attempted to find a peaceful solution but the city's population turned against him and forced him to flee in May 1588. The following year, he was assassinated by a fanatical Dominican monk, bringing the Valois line to a premature end.
The persecution of Jews in Paris began within 48 hours of the city's fall, when they were required to register with police. On 14 May 1941 the Vichy police began deporting Parisian Jews, rounding them up at the Velodrome d'Hiver.
During the 11th century the city spread to the Right Bank. In the 12th and 13th centuries, which included the reign of Philip II Augustus (1180-1223), the city grew strongly. Main thoroughfares were paved, the first Louvre was built as a fortress, and several churches, including the Cathedral of Notre-Dame, were constructed or begun.
Paris' history in the 14th century was thus punctuated by outbreaks of plague, political violence and popular uprisings. In January 1357, Étienne Marcel, the Provost of Paris, led a merchants' revolt in a bid to curb the power of the monarchy and obtain privileges for the city and the Estates General, which had met for the first time in Paris in 1347. After initial concessions by the Crown, the city was retaken by royalist forces in 1358 and Marcel and his followers were killed.
Several schools on the Left Bank were grouped together into the Sorbonne, which counts Albertus Magnus and St. Thomas Aquinas among its early scholars. In the Middle Ages Paris prospered as a trading and intellectual nucleus, interrupted temporarily when the Black Death struck in the 14th century. Under the reign of King Louis XIV, the Sun King, from 1643 to 1715, the royal residence was moved from Paris to nearby Versailles.
In 1870 the Franco-Prussian War ended in a siege of Paris and the Paris Commune, which surrendered in 1871 after a winter of famine and bloodshed. The Eiffel Tower, the best-known landmark in Paris, was built in 1889 in a period of prosperity known as La Belle Époque (The Beautiful period).