The siege of Adramyttium or Assus, c.367-6 BC, saw forces loyal to Artaxerxes II besiege the rebel satrap Ariobarzanes before withdrawing after King Agesilaus of Sparta arrived to help the rebels.
As with much of the Satrap's Revolt the exact details of this siege are unclear. It is mentioned in Xenophon's Agesilaus (II 26), Polyaenus, VII 26 and Demosthenes, For the Liberty of the Rhodians XV, each providing some details.
Ariobarzanes was satrap of Hellespontine Phrygia. He probably originally held that post as regent for Artabazus, son of Pharnabazus, but by the start of the 360s Artabazus was of age, and ready to take over his satrapy. In 368 Ariobarzanes sent an envoy to Greece, where he recruited a mercenary force. His revolt took place after this, but before the outbreak of the third and most serious phase of the Satrap's Revolt (Mausolus, satrap of Caria, took part in the campaign against Ariobarzanes, but was involved in the third phase of the revolt).
Artaxerses II ordered at least three satraps to put down this revolt. Mausolus, satrap of Caria, commanded a fleet that blockaded Ariobarzanes's coastal strongholds. Cotys, satrap of Paphlagonia and king of Thrace besieged Sestus, on the European side of the Hellespont. Finally Autophradates, satrap of Lydia, besieged Ariobarzanes on the Asian side of the straits.
Our sources provide two possible locations for this siege, both on the Adramyttian Gulf (on the southern side of the Troad). Xenophon places it at Assus (Assos), towards the north-western side of the bay. Polyaenus places it at Adramyttium, further to the east, still on the same bay, but on the coast of Mysia.
Polyaenus gives us one incident from the siege. Ariobarzanes was running short of men and provisions because of the close land and sea blockade. He tricked Autophradates into moving away by getting the commander of a nearby island to send a message claiming he was ready to betray the island. Autophradates moved off to try and take advantage of this offer, and while he was away Ariobarzanes moved fresh supplies and reinforcements into the city.
Ariobarzanes's best chance of surviving was external assistance. He asked for help from Athens and Sparta, and both cities responded. The Athenians sent a force under Timotheus, but with orders to only help if it wouldn’t break their treaty with Artaxerxes. When it became clear that Ariobarzanes was rebelling against the king, the Athenians turned away. Rather oddly they then attacked Samos, which was held by troops loyal to Artaxerxes (Demosthenes).
The Spartans sent King Agesilaus, whose main aim was probably to raise funds to help defend Sparta against the rising power of Thebes. Agesilaus was a guest friend of Mausolus, and had an impressive reputation. According to Xenophon Autophradates fled in terror when the Spartans appeared. Cotys also lifted the siege of Sestus, on the European side of the Hellespont.
Mausolus was persuaded to lift the naval blockade. He was also said to have provided Agesilaus with an impressive escort, and then gave him money to take back to Sparta. This is rather odd behaviour - Sparta was in the middle of a desperate crisis in the aftermath of the battle of Leuctra (371 BC) and Agesilaus didn’t come with an army. The suspicion is that Mausolus and his colleagues were actually paying for Spartan mercenaries, ready for their own upcoming revolt.