Now we turn away from Rome to the neighbouring states, most especially Persia.

In the more early ages of the world, whilst the forest that covered Europe afforded a retreat to a few wandering savages, the inhabitants of Asia were already collected into populous cities, and reduced under extensive empires, the seat of the arts, of luxury, and of despotism.

Well, we’re into the origins of the Sassanids now, and the early career of Artaxerxes before he became an emperor:

…it appears that he was driven into exile and rebellion by royal ingratitude, the customary reward for superior merit.

Artaxerxes gains control of Persia. (Balkh is surprisingly far east for a capital.) He decides to reform the Zoroastrian religion, and Gibbon gives us a (probably inaccurate) thumbnail of Zoroastrian theology.

Every mode of religion, to make a deep and lasting impression on the human mind, must exercise our obedience, by enjoining practices of devotion; and must acquire our esteem, by inculcating moral duties analogous to the dictates of our own hearts. The religion of Zoroaster was abundantly provided with the former, and possessed a sufficient portion of the latter.

Gibbon is impressed with the ecological and practical teachings of the Zoroastrians, though not with their religious practice. He is also impressed by Artaxerxes style of government. The Romans have meantime annoyed the Persians by gratuitous sacking of Seleucia and Ctesiphon, and annexation of Osrhoene (which I knew as Edessa). The Persians declare war; the Romans under Alexander Severus invade (this sheds some light on the events of the previous chapter) but are kicked back, and Alexander is killed. Artaxerxes has been weakened too, though Gibbon still has a sneaking admiration for him:

Several of his sayings are preserved. One of them in particular discovers a deep insight into the constitution of government. “The authority of the prince,” said Artaxerxes, “must be defended by a military force; that force can only be maintained by taxes; all taxes must, at last, fall upon agriculture; and agriculture can never flourish except under the protection of justice and moderation.”

He concludes that the Persians, and the Sassanids in particular, may not have been very scientific in their waging of war but were very keen on the practice, and hostile to Rome.