The necropolis was identified in 1925 on the occasion of the reclamation of the Isola Sacra. Other excavations performed in the following years brought the entire necropolis to light, in its full extension of 400 m and with its one hundred and fifty tombs, two thirds of which, relative to the southern group, can be currently visited.The occupation of the necropolis started shortly after the foundation of the Port of Claudius (inaugurated by Nero) and of the settlement of Portus. The tombs, that are built one abreast of another forming groups separated by paths and free areas, are arranged on the two sides of a road, probably of the Trajanian age that connected Portus with Ostia. The most common type of tomb is the family tomb consisting of a square chamber with a fence in front of the cell. The facades, made of bricks and decorated with pilasters, present triangular tympana and frames around the funerary inscriptions. The niches for the funerary urns are situated in the upper part of the internal walls, while there are single arches for burials in the lower part. The floors are mosaic, while the walls and the vaults are decorated with paintings and stuccoes. In the course of time the mixed rite gave way to burials alone, so that the III century tombs situated along the road present only the single arches. The scarceness of available space lead to the reutilization of the existing tombs, mainly during the IV and V centuries. From the inscriptions and the terracotta low reliefs placed on the facades and indicating the trade of the deceased, we understand that the necropolis was used by a the middle class of craftsmen, shopkeepers and merchants; there are not many high-rank personalities present, and even the freedmen and the slaves seem to be a minority. The Christian component is represented only by three inscriptions and a sarcophagus; we actually know that the Christian Cemetery was located at Capo Due Rami.