g 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 _saeculum_.

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 Saeculares_
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
_saeculum_. 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.]

What was the exact location of the sulphur springs, the Tarentum, and
the altar of the infernal gods? I have reason to regard the discovery
of the Altar of Dis and Proserpina as the most satisfactory I have
made, especially because I made it, if I may so express myself, when
away from Rome on a long leave of absence. It took place in the winter
of 1886-87, during my visit to America. At that time the work of
opening and draining the Corso Vittorio Emanuele had just reached a
place which was considered _terra incognita_ by the topographers, and
indicated by a blank spot in the archaeological maps of the city. I
mean the district between the Vallicella (la Chiesa Nuova, the Palazzo
Cesarini, etc.) and the banks of the Tiber near S. Giovanni dei
Fiorentini. The reports spoke vaguely about the discovery of five or
six parallel walls, built of blocks of peperino, of marble steps in
the centre of this singular monument, of gates with marble posts and
architraves, leading to the spaces between the six parallel walls, and
finally, of a column with foliage carved upon its surface. On my
return to Rome, in the spring of 1887, every trace of the monument had
disappeared under the embankment of the Corso Vittorio Emanuele. I
questioned foremen and workmen, I consulted the notebooks of the
con