The significance of the Pass of Darial was that through it the Scythian nomad tribe of the Alani had more than once come to attack Armenia, Media Atropatene and parts of Parthia.
72 the Alani again devastated Media Atropatene and Armenia,(17) and some three years later Volagases I of Parthia proposed a joint Roman/Parthian expedition against the Alani, to be led by one of Vespasian's sons; the latter's younger son was extremely disappointed when the proposal came to nothing (Suetonius, Dom.
The idea of comparing the emperor with Vologeses I of Parthia and his brother Pacorus, ruler of Media Atropatene
, seems to be Tacitus' own work,(44) and the reason for bringing up Pacorus too appears to lie in a wish to balance |inermem et senem', itself an expression by no means as innocent as it looks: Plutarch, and almost certainly the common source, had used these words to characterise one of Galba's first victims, Petronius Turpilianus.(45) In any event, the comparison throws |inermem et senem' into the strongest relief: little as we know about Vologeses, he was surely a good deal younger than Galba (he reigned until 79),(46) and if faced with the threat of being driven from |avito Arsacidarum solio', he would no doubt have armed himself to the teeth.