The Macellum of Naples was the macellum or market building of the Roman city of Neapolis, now known as Naples. Due to the rise of the ground level the macellum is now located beneath the church of San Lorenzo Maggiore. The first construction dates to 5th or 4th century BC when the area was the location of the agora during the Greek period. When Neapolis became a Roman possession it was eventually transformed into a macellum. This structure was covered by a mudslide in the 5th century AD, probably as a result of flooding.
An early Christian basilica was constructed over the remains of the covered macellum. Consequently, this basilica was replaced by new construction over the centuries. As a result, the mud slide preserved the remains of the macellum,
The macellum had an entrance to the north, where the Via dei Tribunali runs now. The rectangular building consists of a porticoed area with workshops and an internal open courtyard with mosaic floors. In the middle of the courtyard was a tholos, a circular building used for food selling. Small tabernae, a laundry and the treasury can still be recognized.
Today the macellum can be visited as a part of the monumental complex of San Lorenzo Maggiore.
References:The Arch of Constantine is situated between the Colosseum and the Palatine Hill. It was erected by the Roman Senate to commemorate Constantine I's victory over Maxentius at the Battle of Milvian Bridge in 312. Dedicated in 315, it is the largest Roman triumphal arch. The arch spans the Via triumphalis, the way taken by the emperors when they entered the city in triumph.
Though dedicated to Constantine, much of the decorative material incorporated earlier work from the time of the emperors Trajan (98-117), Hadrian (117-138) and Marcus Aurelius (161-180), and is thus a collage. The last of the existing triumphal arches in Rome, it is also the only one to make extensive use of spolia, reusing several major reliefs from 2nd century imperial monuments, which give a striking and famous stylistic contrast to the sculpture newly created for the arch.
The arch is 21 m high, 25.9 m wide and 7.4 m deep. Above the archways is placed the attic, composed of brickwork reveted (faced) with marble. A staircase within the arch is entered from a door at some height from the ground, on the west side, facing the Palatine Hill. The general design with a main part structured by detached columns and an attic with the main inscription above is modelled after the example of the Arch of Septimius Severus on the Roman Forum.