The Basilica of Saint Clement, dedicated to Pope Clement I, is especially notable for its three historical layers. The 12th-century basilica is built on top of a well-preserved 4th-century church (with many frescoes), which was built next to a 3rd-century Mithraic Temple. For an admission fee, it is possible to explore the excavations of the lower two levels, which is a fascinating journey into the history of Rome.
This ancient church was transformed over the centuries from a private home that was the site of clandestine Christian worship in the 1st century to a grand public basilica by the 6th century, reflecting the emerging Catholic Church's growing legitimacy and power.
The current basilica was rebuilt by Cardinal Anastasius, ca 1099-ca. 1120. Today, it is one of the most richly adorned churches in Rome. The ceremonial entrance (a side entrance is ordinarily used today) is through an atrium surrounded by arcades, which now serves as a cloister, with conventual buildings surrounding it. Fronting the atrium is the chaste facade of Carlo Stefano Fontana, supported on antique columns, and his little campanile (illustration). The basilica church behind it is in three naves divided by arcades on ancient marble or granite columns, with Cosmatesque inlaid paving. The 12th-century schola cantorum incorporates marble elements from the original basilica. Behind it, in the presbytery is a ciborium raised on four gray-violet columns over the shrine of Clement in the crypt below. The episcopal seat stands in the apse, which is covered with mosaics on the theme of the Triumph of the Cross that are a high point of Roman 12th century mosaics.
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.