The Parissi, a sub-tribe of the Celtic Senones inhabited the Paris area from around the middle of the 3rd century BC. One of the area’s major north-south trade routes crossed the Seine, this meeting place of land and water trade routes gradually became a town and an important trading centre. The Parisii traded with many river towns as far away as Spain, and minted their own coins for that purpose.
The Romans conquered the Paris basin in 52 BC and, after making the island a garrison camp, began extending their settlement in a more permanent way to Paris’ Left Bank. The Gallo-Roman town was originally called Lutetia. It became a prosperous city with a forum, baths, temples, theatres, and an amphitheatre.
By the end of the Roman Empire, the town was known simply as Parisius in Latin and Paris in French. Christianinty was introduced in the middle of the 3rd century AD. According to tradition, it was brought by Saint Denis, the first Bishop of Paris. When he refused to renounce his faith, he was beheaded on the hill which became known as the “Mountain of Martyrs”, eventually “Montmartre”. His burial place became an important religious shrine; the Basilica of Saint-Denis was built there and became the burial place of the French Kings.
Clovis the Frank, the first king of the Merovingian dynasty, made the city his capital from 508. Fortification of the Ile de France failed to prevent sacking by Vikings in 845 but Paris’s strategic importance—with its bridges preventing ships from passing—was established by successful defence in the Siege of Paris (885–86). In 987 Hugh Capet, Count of Paris, Duke of the Franks was elected King of the Franks. Under the rule of the Capetian kings, Paris gradually became the largest and most prosperous city in France.