aces had to contract for the proper supply of
horses and men. The drivers (_aurigae, agitatores_), who were mostly
slaves, were sometimes held in high repute for their skill, although
their calling was regarded with contempt. The horses most valued were
those of Sicily, Spain and Cappadocia, and great care was taken in
training them. Chariots with two horses (_bigae_) or four (_quadrigae_)
were most common, but sometimes also they had three (_trigae_), and
exceptionally more than four horses. Occasionally there was combined
with the chariots a race of riders (_desultores_), each rider having two
horses and leaping from one to the other during the race. At certain of
the races the proceedings were opened by a _pompa_ or procession in
which images of the gods and of the imperial family deified were
conveyed in cars drawn by horses, mules or elephants, attended by the
colleges of priests, and led by the presiding magistrate (in some cases
by the emperor himself) seated in a chariot in the dress and with the
insignia of a triumphator. The procession passed from the capitol along
the forum, and on to the circus, where it was received by the people
standing and clapping their hands. The presiding magistrate gave the
signal for the races by throwing a white flag (_mappa_) on to the
course.

Next in importance to the Circus Maximus in Rome was the _Circus
Flaminius_, erected 221 B.C., in the censorship of C. Flaminius, from
whom it may have taken its name; or the name may have been derived from
Prata Flaminia, where it was situated, and where also were held plebeian
meetings. The only games that are positively known to have been
celebrated in this circus were the _Ludi Taurii_ and _Plebeii_. There is
no mention of it after the 1st century. Its ruins were identified in the
16th century at S. Catarina dei Funari and the Palazzo Mattei.

A third circus in Rome was erected by Caligula in the gardens of
Agrippina, and was known as the _Circus Neronis_, from the notoriety
which it obtained through the Circensian pleasures of Nero. A fourth was
constructed by Maxentius outside the Porta Appia near the tomb of
Caecilia Metella, where its ruins are still, and now afford the only
instance from which an idea of the ancient circi in Rome can be
obtained. It was traced to Caracalla, till the discovery of an
inscription in 1825 showed it to be the work of Maxentius. Old
topographers speak of six circi, but two of these appear to be
imagina