§328. Roman Circuses.--The games of the circus were the oldest of the free exhibitions at Rome and always the most popular. The word _circus_ means simply a ring and the _lūdī circēnsēs_ were therefore any shows that might be given in a ring. We shall see below (§343) that these shows were of several kinds, but the one most characteristic, the one that is always meant when no other is specifically named, is that of chariot races. For these races the first and really the only necessary condition is a large and level piece of ground. This was furnished by the valley between the Aventine and Palatine hills, and here in prehistoric times the first Roman race course was established. This remained _the_ circus, the one always meant when no descriptive term was added, though when others were built it was called sometimes by way of distinction the Circus Maximus. None of the others ever approached it in size, in magnificence, or in popularity. §329. The second circus to be built at Rome was the _circus Flāminius_, founded in 221 B.C. by the same Caius Flaminius, who built the Flaminian road. It was located in the southern part of the Campus Martius (§317), and like the Circus Maximus was exposed to the frequent overflows of the Tiber. Its position is fixed beyond question, but the actual remains are very scanty, so that little is known of its size or appearance. The third to be established was that of Caius (Caligula) and Nero, named from the two emperors who had to do with its construction, and erected, therefore, in the first century A.D. It lay at the foot of the Vatican hill, but we know little more of it than that it was the smallest of the three. These three were the only circuses within the city. In the immediate neighborhood, however, were three others. Five miles out on the _via Portuēnsis_ was the circus of the Arval Brethren. About three miles out on the Appian way was the Circus of Maxentius, erected in 309 A.D. This is the best preserved of all, and a plan of it is shown in the next paragraph. On the same road, some twelve miles from the city, in the old town of Bovillae, was a third, making six within easy reach of the people of Rome. [Illustration: FIGURE 139. PLAN OF THE CIRCUS OF MAXENTIUS]