Suger's abbey-church demained unfinished, and we may imagine that the old Carolingian nave, by then four centuries old, had begun to fall into ruin. Thus, in 1231 the abbot Eudes Clément du Mez embarked on its reconstruction, the most spectacular part of which was the creation of the two transept rose windows. The works benefited from the presence of the renowned architect Pierre de Montreuil, and involved modifying most of the royal tombs. In 1264, the bodies of the kings and queens were regrouped beneath the transept crossing. The "Commande de Saint Louis" featured sixteen gisants that displayed, in symbolic fashion, the dynastic continuity of one Merovingian and seven Carolingian rulers followed by eight Capetians. This was the beginning of the famous "cemetery of kings". The church was completed in 1281. In the monastery, this period of opulence was reflected in the reconstruction of most of the establishment's buildings. At the same time, the architectural framework of the abbey's main cemetery reached its limits with the construction of the Sainte-Geneviève, Saint-Michel-du-Charnier and Madeleine churches. It was only in 1242 that Saint-Jacques-a church located to the south of the abbey, and reserved for the monks' servants-was mentioned for the first time.

As its settlement became denser, the monastic borough took precedence over other surrounding settlement. The urban extension overflowed the boundary wall, whose moats became progressively silted up. Nevertheless, the Croult, -the canal that supplied them with water-was preserved, contained within carefully maintained stockade-type walls. This river was a driving force in the economic life of the town. Gradually, the riverside became home to a series of workshops; in particular, the quality of the water favoured the development of drapery and tannery activities. In 1229, the abbey built a second market -hall which forced it to transfer the town's original jail to the Porte Compoise, which became the châtelet châtelet
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a fortress defending the Compoise gate of the castellum sancti Dionysii, which became the seat of the criminal courts of the monastic borough .

The town continued to grow, both at the gates of the castellum Castellum sancti Dionysii
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fortification built by Charles the Bald in 869 around the abbey of Saint-Denis; the zone delimited by the walls of this castellum. and along the four roads leading to it. Saint-Denis linked up with the settlement of Saint-Marcel, Estrée and Saint-Remi. We know more about the "terre de Saint-Marcel", because archives contain a number of documents relating to the never-ending disputes between the abbey and the lords of Montmorency. The legal dispute, which mostly concern the public roads, testify to the intense trade that must have benefited the development of this inner suburb. The Sainte-Croix church, mentioned in 1205, was probably the result of the splitting up of the Saint-Marcel parish. We do not know the exact location of the Saint-Nicolas-des-Aulnes church, which probably stood between the Seine and l'Estrée.