Campus Martius in the context of "Capitoline Hill"

In ancient Roman religion and mythology, Mars (Latin: Mārs, pronounced [maːrs]) is the god of war and also an agricultural guardian, a combination characteristic of early Rome. He is the son of Jupiter and Juno, and was pre-eminent among the Roman army's military gods. Most of his festivals were held in March, the month named for him (Latin Martius), and in October, the months which traditionally began and ended the season for both military campaigning and farming.

Under the influence of Greek culture, Mars was identified with the Greek god Ares, whose myths were reinterpreted in Roman literature and art under the name of Mars. The character and dignity of Mars differs in fundamental ways from that of his Greek counterpart, who is often treated with contempt and revulsion in Greek literature. Mars's altar in the Campus Martius, the area of Rome that took its name from him, was supposed to have been dedicated by Numa, the peace-loving semi-legendary second king of Rome; in Republican times it was a focus of electoral activities. Augustus shifted the focus of Mars's cult to within the pomerium (Rome's ritual boundary), and built a temple to Mars Ultor as a key religious feature of his new forum.

The Secular or Saecular Games (Ludi Saeculares) was an ancient Roman religious celebration involving sacrifices, theatrical performances, and public games (ludi). It was held irregularly in Rome for three days and nights to mark the ends of various eras (saecula) and to celebrate the beginning of the next. In particular, the Romans reckoned a saeculum as the longest possible length of human life, either 100 or 110 years in length; as such, it was used to mark various centennials, particularly anniversaries from the computed founding of Rome.

According to Roman mythology, the Secular Games began as the Tarentine Games (Ludi Tarentini) when a Sabine man called Valesius prayed for a cure for his children's illness and was supernaturally instructed to sacrifice on the Campus Martius to Dis Pater and Proserpina, deities of the underworld. Some ancient authors traced official celebrations of the Games as far back as 509 BC, but the only clearly attested celebrations under the Roman Republic took place in 249 and in the 140s BC. They involved sacrifices to the underworld gods over three consecutive nights. The Games were revived in 17 BC by Rome's first emperor Augustus, with the nocturnal sacrifices on the Campus Martius now transferred to the Moerae (fates), the Ilythiae (goddesses of childbirth), and Terra Mater ("Mother Earth"). The Games of 17 BC also introduced day-time sacrifices to Roman deities on the Capitoline and Palatine hills. Certain sacrifices were unusually specified to be performed by married women. Each sacrifice was followed by theatrical performances. Later emperors held celebrations in AD 88 and 204, after intervals of roughly 110 years. However, they were also held by Claudius in AD 47 to celebrate the 800th anniversary of Rome's foundation, which led to a second cycle of Games in 148 and 248. The Games were abandoned under later Christian emperors.

Piazza del Campidoglio ("Capitoline Square") is a public square (piazza) on the top of the ancient Capitoline Hill, between the Roman Forum and the Campus Martius in Rome, Italy. The square includes three main buildings, the Palazzo Senatorio (Senatorial Palace) also known as the Comune di Roma Capitale (City Hall), and the two palaces that make up the Capitoline Museums, the Palazzo dei Conservatori and the Palazzo Nuovo, considered to be one of the oldest national museums, founded in 1471 when Pope Sixtus IV donated some of the museum's most impressive statues, the She-wolf, the Spinario, the Camillus and the colossal head of emperor Constantine. Over the centuries the museums' collection has grown to include many of ancient Roman's finest artworks and artifacts. If something was considered too valuable or fragile in Rome and a copy was made in its place for display, the original is likely now on display in the Capitoline Museum. The hilltop square was designed by Michelangelo in the 16th century. at the behest of Pope Paul III.

The Ara Pacis Augustae (Latin, "Altar of Augustan Peace"; commonly shortened to Ara Pacis) is an altar in Rome dedicated to the Pax Romana. The monument was commissioned by the Roman Senate on July 4, 13 BC to honour the return of Augustus to Rome after three years in Hispania and Gaul and consecrated on January 30, 9 BC. Originally located on the northern outskirts of Rome, a Roman mile from the boundary of the pomerium on the west side of the Via Flaminia, the Ara Pacis stood in the northeastern corner of the Campus Martius, the former flood plain of the Tiber River and gradually became buried under 4 metres (13 ft) of silt deposits. It was reassembled in its current location, now the Museum of the Ara Pacis, in 1938, turned 90° counterclockwise from its original orientation so that the original western side now faces south.

The Column of Antoninus Pius (Italian: Colonna di Antonino Pio) is a Roman honorific column in Rome, Italy, devoted in AD 161 to the Roman emperor Antoninus Pius, in the Campus Martius, on the edge of the hill now known as Monte Citorio, and set up by his successors, the co-emperors Marcus Aurelius and Lucius Verus. The column itself is now destroyed, but its base is preserved.

The Aurelian Walls (Italian: Mura aureliane) are a line of city walls built between 271 AD and 275 AD in Rome, Italy, during the reign of the Roman Emperor Aurelian. They superseded the earlier Servian Wall built during the 4th century BC.

The walls enclosed all the seven hills of Rome plus the Campus Martius and, on the right bank of the Tiber, the Trastevere district. The river banks within the city limits appear to have been left unfortified, although they were fortified along the Campus Martius. The size of the entire enclosed area is 1,400 hectares (3,500 acres). The wall cut through populated areas: in reality the city at the time embraced 2,400 hectares (5,900 acres). Pliny the Elder in the first century AD suggested that the densely populated areas, extrema tectorum ("the limits of the roofed areas") extended 2.8 kilometres (1.7 mi) from the Golden Milestone in the Forum (Natural History 3.67).