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 Stoic attempt to harmonise the old religious beliefs with philosophic theories of the universe[555].

Varro, following his teacher, held the Stoic doctrine of the _animus mundi_ the Divine principle permeating all material things which, in combination with them, constitutes the universe, and is Nature, Reason, God, Destiny, or whatever name the philosopher might choose to give it.

The universe is divine, the various parts of it are, therefore, also divine, in virtue of this informing principle.