Campus, in Roman antiquity, a common public park, or vacant space near the city for shows, combats, exercises, and similar uses. Ancient Rome possessed eight campi. The term is derived from the ancient Sicilian word for race course. The Campus Martius was the most celebrated of the campi of ancient Rome. It lay outside of the walls of Rome, and consisted of the level ground between the Quirinal, Capitoline, and Pincian mounts, and the river Tiber. It received the appellation Martius from its being consecrated to the god Mars. It was originally set apart for military exercises and contests. Here the comitia centuriata assembled in mass meeting, and subsequently the comitia tributa; here stood the villa publica for the use of the Roman magistrates and the foreign ambassadors, who were not permitted to enter the city limits. It gradually became a suburban pleasure ground, and was laid out with gardens, shady walks, baths, a race course, and theatres. Julius Caasar built there marble halls for the comitia, Agrippa erected the first public baths and the Pantheon, Augustus Caesar the Egyptian obelisk and his own mausoleum, and Statilius Taurus the first amphitheatre of stone. Under the later emperors the place became crowded with public buildings, and subsequently with private residences.

Among the former, the most celebrated were Domi-tian's temple of Minerva Chalcidia, and the pillar of Antoninus. Under Aurelian, the Campus Martius was enclosed within the city boundaries. Campo Marzo is the name given to one of the districts of modern Rome on the northern part of the old Campus Martius. - The Campus Sceleratus, or polluted field, was a place beyond the walls of ancient Rome, where vestal virgins who had been untrue to their oaths of chastity were buried alive.