Around the middle of the 3rd century, the inhabitants of the suburbs of Narbo Martius, pushed by  the deteriorating security situation, started taking refuge behind the protection of the city walls. Little by little, the Clos de  la Lombarde was abandoned and left to the looting of materials pickers.  But during the last decades of the 4th century, with Christianity progressing, a church was erected at the site of the House  with the Porticoes.  It is undoubtedly the first place of Christian worship in NARBONNE, older than the church of Saint-Rustique.  This religious building, partly built with the materials recovered from the Roman buildings, occupied about one-third of the  surface of the House with the Porticoes whose south-west and south-east walls it partially reused.  27 meters long, 12.65 meters wide, this basilica follows the plan of the early Christian churches of Syria.  Three naves of 17 m in length were the part reserved for the faithful.  The choir was elevated versus the naves by about 1 meter  and was constituted by a central apse hall in the center and  two side rooms.  Under the choir, there was a crypt in which an in-ground pit  that may have been a baptismal pool was found.  Beneath the paving of the basilica some 50 tombs were found: there were sarcophagi in seashell limestone from St. Lucia,  still in place, including one in front of the choir, in the central nave, which must have been the burial place of an important  unidentified person. Also, graves directly in the ground were found as well as some that were protected by stacked tiles,  and the bodies of children that were buried in amphoras.  To this day, the dedication of this church has not been found.   After Narbo Martius was taken by the Visigoths in 412, the district of Clos de la Lombarde where a small agglomeration had constituted itself was definitively abandoned, the church was destroyed, and the grounds were returned to agricultural use which continued until 1972.