CAMPUS MARTIUS, a large plain in the suburbs of ancient Rome, lying between the Quirinal and Capitoline Mounts and the Tiber, and so called because it was consecrated to Mars, and set apart for military sports and exercises. Here also the comitia of the centuries were held, and races were run either with chariots or single horses; and here also stood the villa publica, or palace for the reception of ambassadors, who were not permitted to enter the city. The place was also nobly decorated with statues, arches, columns, porticoes, &c. It was included within the city walls by Aurelian.