THE WALLS AND GATES
Taking into account a long history of research and studies, and the relative bibliography, which is the product of at least two periods of fervid debate on the subject-the 1930s and 1940s and the 1970s and 1980s-what we know today about the walls can be summed up briefly as follows. The ridge of the terrace on which Pompeii stood was first surrounded by walls in the first half of the sixth century BC. Remains of the walls have been identified at Porta Nocera2 and between Porta Nocera and Tower III, beneath the Tower of Mercury and at Porta Vesuvio; traces of it have come to light at Porta Ercolano (see Map 2). The circuit of this fortification, roughly coinciding with that of the subsequent ones in the northwest and southeast sectors, seems to have defined for the first time the area of more than 65 ha (160 acres) that the city was to keep up to the end. From that time on a wall surrounded the entire plateau along the so-called “tactical ridge,” defined by the conformation of the margins of the lava front which in protohistoric times had formed the hill on which the city stood (Figure 11.1).