Campus Martius means "Field of Mars" in Latin and was a publicly owned area of Rome. It was about 2 square kilometers wide. According to legend, the Campus Martius was owned by the last king of Rome, Tarquinius Superbus. It was a field of wheat, and was burned during the revolution which established the Roman Republic. In the first centuries after Rome's founding, the Campus Martius was outside of the Servian Wall, so it was used as a pasture and a training place for Rome's military. This is why the name is dedicated to Mars. Later, the field was used to celebrate military triumph. In 221 BC, the Circus Flaminius was built in the Campus Martius. Starting in the time of Sulla, lots from the Campus Martius were sold or granted to influential Romans. During the Augustan Period, the area officially became part of the city. The Ara Pacis (Altar of Peace) was also built to represent the stabilizing of the empire under Augustus. Marcus Agrippa had the swampy part of the grounds made into the Baths of Agrippa. He also built the Porticus Argonautarum, the Pantheon, and the Aqua Virgo. More buildings were made including the Mausoleum of Augustus, the Theater of Marcellus, the temple for Isis, and the baths and bridges built by Nero. Domitianus eventually built a stadium and an Odeion. The area was then filled with temples, buildings, obelisks, etc. Oddly enough, there is no monument dedicated solely to Mars in the later Roman period. The Aurelian Walls were built around 270, which enclosed the Campus Martius.
