The royal basilica of Saint-Denis belonged to a prosperous and powerful Benedictine abbey during the Middle Ages and was the first monumental masterpiece of Gothic art. Enlarged in the 7th century through the impetus of Dagobert 1 (639 AD) who was buried there, followed by his son Clovis II (657 AD), the monastery quickly became one of the main burial sites for the Merovingian dynasty. From the time of Hugues Capet (987-996), the first Capetian monarch, the basilica was firmly established as the definitive “Cemetery of Kings”. It continued to develop, and proceeded to become one of the most powerful Benedictine abbeys of the Middle Ages. The royal necropolis contains tombs of French kings with remarkable funerary sculpture dating from 12th to 16th centuries.
Crypte Archéologique, stretching 118 meters under the Parvis du Notre Dame, was built by the city of Paris in order to house the archeological finds discovered during the excavation undertaken in 1965 by the Direction des Antiquites historiques de I'Ile de France and the Commission du Vieux Paris. It contains ruins of Roman quaysides, ramparts and hypocausts, medieval cellars, shops and pavements, the foundations of the Eglise Ste-Geneviève-des-Ardens, an 18th-century foundling hospital and a 19th-century sewer. Imbedded in the surface of the plaza itself are brass strips which locate the streets and buildings that were removed.