Strabo Geography 15.3.12

[12] The part of Babylonia formerly called Sitacene, and afterwards Apolloniatis, ¹ is situated near Susis.

Above both, on the north and towards the east, are the Elymaei ² and the Paraetaceni, predatory people relying for security on their situation in a rugged and mountainous country. The Paraetaceni lie more immediately above the Apolloniatae, and therefore annoy them the more. The Elymaei are at war with this people and with the Susians, and the Uxii with the Elymaei, but not so constantly at present as might be expected, on account of the power of the Parthians, to whom all the inhabitants of those regions are under subjection. When therefore the Parthians are quiet, all are tranquil, and their subject nations. But when, as frequently happens, there is an insurrection, which has occurred even in our own times, the event is not the same to all, but different to different people. For the disturbance has benefited some, but disappointed the expectation of others.

Such is the nature of the countries of Persis and Susiana.