he present urban plan of the town of Niebla is located upon a type tell formation, generated by the superposition of architectural remains and other sediments with urban elements, as a result of the settlements in this location from protohistoric times up to the present moment.

Although the most recent excavations are still being studied, it is evident that the town has gone through different stages, during which its urban plan and its extent have considerably varied.

Former excavations had confirmed the location of the Protohistoric and Roman cities in the north area of the tell, but new data have proven that the settlement within the walls prior to the medieval period cannot have been bigger than the area within the present boundaries, aproximately. The latest enclosure, at 40m above sea level in the south-east end, is believed to be only a possible expansion dating, maybe, from the 12th-13th centuries.

Since it was assumed that the present urban plan of blocks and streets corresponded to the Roman plan, and that the muslim settlement had not modified it, the centre of the ancient town prior to the expansion dating the 12th and 13th centuries must have not been located on the axis Puerta Socorro-Plaza de Santa María-Puerta del Agua, but to the north, being that axis a part external to the Roman pomerium.

This fact involves that the present urban plan is only the inheritance of the most recent settlement, since that during centuries a progressive urban degradation had left big areas unoccupied within the walls, which have recently been urbanized according to modern urban criteria. That is why the names of some streets show their connection to empty or farming areas, ej.: Campo Castillo, Olivar de…, Huertos de…,etc.

From that it follows that the expansion that reflects the wall plan corresponds to the biggest territorial expansion of the Ibn Mahfoh's Labla, and those of the califal and taifas periods would not exceed the one of Roman and pre-Roman periods, that is to say, only in the area limited by the height of 40m above sea. Its archaeological proof would be the the tell-type formations, whereas there were hardly any ancient formations in the western area. The latest muslim wall spreads over an area of aproximately 16 has.