The origin of the sæcular games seems to be this: In the early days of Rome the northwest section of the Campus Martius, bordering on the Tiber, was conspicuous for traces of volcanic activity. There was a pool here called Tarentum or Terentum, fed by hot sulphur springs, the efficiency of which is attested by the cure of Volesus, the Sabine, and his family, described by Valerius Maximus. Heavy vapors hung over the springs, and tongues of flame were seen issuing from the cracks of the earth. The locality became known by the name of the fiery field (_campus ignifer_), and its relationship with the infernal realms was soon an established fact in folk-lore. An altar to the infernal gods was erected on the borders of the pool, and games were held periodically in honor of Dis and Proserpina, the victims being a black bull and a black cow. Tradition attributed this arrangement of time and ceremony to Volesus himself, who, grateful for the recovery of his three children, offered sacrifices to Dis and Proserpina, spread _lectisternia_, or reclining couches, for the gods, with tables and viands before them, and celebrated games for three nights, one for each child which had been restored to health. In the republican epoch they were called _Ludi Tarentini_, from the name of the pool, and were celebrated for the purpose of averting from the state the recurrence of some great calamity by which it had been afflicted. These calamities being contingencies which no man could foresee, it is evident that the celebration of the _Ludi Tarentini_ was in no way connected with definite cycles of time, such as the _sæculum_. Not long after Augustus had assumed the supreme power, the _Quindecemviri sacris faciundis_ (a college of priests to whom the direction of these games had been intrusted from time immemorial) announced that it was the will of the gods that the _Ludi Sæculares_ should be performed, and misrepresenting and distorting events and dates, tried to prove that the festival had been held regularly at intervals of 110 years, which was supposed to be the length of a _sæculum_. The games of which the Quindecemviri made this assertion were the Tarentini, instituted for quite a different purpose, but their suggestion was too pleasing to Augustus and the people to be despised. Setting aside all disputes about chronology and tradition, the celebration was appointed for the summer of the year 17 B. C. [Illustration: Plan and section of the Altar of Dis and Proserpina.]