he first to strike a direct blow at the popular belief in the
efficacy of prayer and sacrifice, by openly declaring that the gods
did not interest themselves in mankind,[550]--the same Epicurean
doctrine preached afterwards by Lucretius. It may indeed be doubted
whether this doctrine became popular, or acceptable even to the
cultured classes; but the fact remains that the same man who did
more than any one before Virgil to glorify the Roman character and
dominion, was the first to impugn the belief that Rome owed her
greatness to her divine inhabitants.

But in the next generation there arrived in Rome a man whose teaching
had so great an influence on the best type of educated Roman that, as
we have already said, he may almost be regarded as a missionary.[551]
We do not know for certain whether Panaetius wrote or taught about the
nature or existence of the gods; but we do know that he discussed the
question of divination[552] in a work [Greek: Peri pronoias], where he
could hardly have avoided the subject. In any case the Stoic doctrines
which he held, themselves ultimately derived from Plato and the Old
Academy, were found capable in the hands of his great successor
Posidonius of Rhodes of supplying a philosophical basis for the
activity as well as the existence of the gods. These men, it must
be repeated, were not merely professed philosophers, but men of the
world, travellers, writing on a great variety of subjects; they were
profoundly interested, like Polybius, in the Roman character and
government; they became intimate with the finer Roman minds, from
Scipio the younger to Cicero and Varro, and seem to have seen clearly
that the old rigid Stoicism must be widened and humanised, and its
ethical and theological aspects modified, if it were to gain a real
hold on the practical Roman understanding. We have already seen[553]
how their modified Stoic ethics acted for good on the best Romans
of our period. In theology also they left a permanent mark on Roman
thought; Posidonius wrote a work on the gods, which formed the basis
of the speculative part of Varro's _Antiquitates divinae_, and almost
certainly also of the second book of Cicero's de _Natura Deorum_[554].
Other philosophers of the period, even if not professed Stoics, may
have discussed the same subjects in their lectures and writings,
arriving at conclusions of the same kind.

It is chiefly from the fragments of Varro's work that we learn
something of the Sto