9525  Sources are silent regarding the events following the first Persian campaign but the silence in itself is an indication of the peace that prevailed and that the Persians stopped being a threat to the Roman East . The evidence for the second campaign is meager ; Zosimus is the only one to mention it specifically . A passage in the Sibylline Oracles is interpreted by Hartmann as an indication of the second invasion . The campaign took place in 266 or 267 and was aimed directly at Ctesiphon ; Odaenathus reached the walls of the Persian capital but had to cancel the siege and march north to face the influx of Germanic riders attacking Anatolia . 