place of land and water trade routes gradually became an important trading centre. The Parisii traded with many river towns (some as far away as the Iberian Peninsula) and minted their own coins for that purpose. The Romans conquered the area in 52 BC and began their settlement on Paris's Left Bank. It became a prosperous city with a forum, baths, temples, theatres, and an amphitheatre. Christianity was introduced in the middle of the 3rd century AD by Saint Denis, the first Bishop of Paris. According to legend, when Denis refused to renounce his faith before Roman authorities, he was beheaded on the hill that became known as Mons Martyrum (Latin "Hill of Martyrs"), later "Montmartre". The legend further states that Denis walked headless from this hill to the north of the city. The place that he finally fell and was buried became an important religious shrine, the Basilica of Saint-Denis. Clovis the Frank, the first king of the Merovingian dynasty, made the city his capital in 508. As the Frankish domination of Gaul began, there was a gradual immigration by the Franks to Paris and the Parisian Francien dialects were born. Fortification of the Île de la Cité failed to avert 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 (comte de Paris) and Duke of the Franks (duc des Francs), was elected King of the Franks (roi des Francs). Under the rule of the Capetian kings, Paris gradually became the largest and most prosperous city in France. The Kings of France enjoyed getting away from Paris and hunting in the game-filled forests of the region. They built palatial hunting lodges, most notably Palace of Fontainebleau and the Palace of Versailles. From the time of Louis XIV to the French Revolution, Versailles was the official residence of the Kings and the seat of the French government. Île-de-France became the term used for the territory of Paris and the surrounding province, which was administered directly by the King. During the French Revolution, the royal provinces were abolished and divided into departments, and the city and region were governed directly by the national government. After World War II, as Paris faced a major housing shortage, hundreds of massive apartment blocks for low-income residents were built around the edges