The Roman city of Cemenelum was founded in the 1st century AD as a staging post for Roman troops in the Alpes Maritime region and it later became the regional capital. Favorably located, Cemenelum was chosen as the principal seat of the province of Alpes Maritimae by Augustus in 14 BC. Later, the Romans settled further inland, on the opposite side of the river Paillon. Remains of the town on the Hill of Cimiez date to the 3rd century AD.
The Amphitheater at the northern end of the site was originally built of wood and seated only 500-600. It was later rebuilt in stone during the Severan dynasty (AD 193-217) with its capacity expanded to 5000 persons. The vaulted remains at Nice may be compared to other small amphitheaters in garrison towns in the Roman Empire. Seating in the amphitheater reflected class distinctions between officers and enlisted men, with the structure at Nice-Cimiez divided into two sections reached by separate entrances.
The amphitheatre is not as big or as well-preserved as those found in Arles or Nimes, but along with the Roman baths and arena, visitors can gain a sense of wonder into Roman life by paying a visit to the archaeological museum (Musée Archéologique de Nice-Cimiez) on Avenue des Arènes.
The Roman baths complex is the largest known in Gaul.
The Church of St Donatus name refers to Donatus of Zadar, who began construction on this church in the 9th century and ended it on the northeastern part of the Roman forum. It is the largest Pre-Romanesque building in Croatia.
The beginning of the building of the church was placed to the second half of the 8th century, and it is supposed to have been completed in the 9th century. The Zadar bishop and diplomat Donat (8th and 9th centuries) is credited with the building of the church. He led the representations of the Dalmatian cities to Constantinople and Charles the Great, which is why this church bears slight resemblance to Charlemagne's court chapels, especially the one in Aachen, and also to the Basilica of San Vitale in Ravenna. It belongs to the Pre-Romanesque architectural period.
The circular church, formerly domed, is 27 m high and is characterised by simplicity and technical primitivism.