In 302 Mithridates II fell under suspicion of conspiring with Cassander against Antigonus and was killed near Cius. His son Mithridates III of Cius inherited the dynasty, but was warned by his friend Demetrius that he too was in danger from Antigonus and fled to Paphlagonia. Here he ruled for thirty six years (302-266) at some stage proclaiming himself king Mithridates I Ctistes, founder of the kingdom of Pontus and of the line of Pontic kings. After his escape from Antigonus he had established his base at Cimiata in Paphlagonia, a "strong fortress" in the mountainous country of Olgassys. For twenty years there is almost complete silence about the new kingdom. Appian (Mith. 9) does say that Mithridates took advantage of the Macedonians' ascholia to expand over the whole of Cappadocia and neighbouring areas. Given the flexibility of the terms "Pontus" and "Cappadocia", Appian is probably referring to an expansion into what we know as Pontus..... 1
Paphlagonians, Cappadocians and Cataonians — the main ethnicities of Northern and Central Anatolia, which earlier had supported Darius III, local satraps and dynasts — met Alexander the Great with a great deal of hostility in 334 BC, when he came to Asia Minor. In 302 BC, when the kingdom of Pontus was formed in Paphlagonia and Cappadocia, anti-Macedonian sentiment was still common among the local population. The first Pontic ruler, Mithridates I Ctistes, who was in the process of creating a new kingdom in Pontic Cappadocia, took advantage of this anti-Macedonian sentiment to win the local inhabitants over to his side, who remembered their rather cruel treatment by Alexander's governors and the Macedonian diadochs Eumenes of Cardia, Perdiccas and Antigonus. Mithridates, himself pursued by Antigones for treason (Diod. XX. 111. 4; Plut. Dem. 4; App. Mithr. 9; Ps.-Luc. Macr. 13), was sought by the Paphlagonians, Cappadocians and Greeks from coastal cities as a person to head the struggle against Macedonian expansion.
By adopting the royal title in 298/297 BC, at the same time as Zipoetes of Bithynia, the ruler of Pontus demonstrated that he was hostile to Lysimachus, as both dynasts were anxious about his domination in Thrace and north-western Asia Minor along with a part of the Black Sea coastal zone. We are unaware of any direct military confrontation between Mithridates of Pontus and Lysimachus, but we know about the constant struggle of Bithynia against Antigonus (Diod. XIX. 60. 3) and about that kingdom's actions against Lysimachus and his strategoi (Memn. X; XX. 3). The common threat to Bithynia and Pontus from Lysimachus brought Zipoetes and Mithradates Ctistes closer to each other. It also gave to Mithridates new sympathisers from the Anatolian population, which was frightened of the Macedonian generals' hegemony (cf. Strabo XII. 3. 41; App. Mithr. 9; Diod. XX. 111. 4).
Negative attitudes to Hellenic-Macedonian expansion in North Anatolia did not change even after 281 BC when Lysimachus was killed in the battle of Corupedion. The Seleucids thereafter took it upon themselves to carry out an expansive policy in northern Asia Minor, which inevitably brought them into conflict with the kingdom of Pontus....
On the wave of success after the battle of Corupedion in 281/280 BC, when Lysimachus was already dead, his conqueror Seleucus I sent an army under the general Diodorus to Cappadocia with the task of conquering it. He was also ordered to deprive Mithridates I in Pontus of his autonomy and independence, because he had earlier fallen away from Antigonus-the-one-Eyed, who was the possessor of Syria and the whole of Asia, as Seleucus I himself was later. This military campaign failed (Trog. Prol. 17).... Eastern and north-eastern regions of Anatolia, which were under the power of the Pontic king, managed to keep their independence by military force. But the threat of a new Seleucid invasion still remained, causing Mithridates I of Pontus to respond to Heraclea's request to enter the alliance against Seleucus. Some other cities — Byzantium, Calchedon, Tieum, Cierus — along with Bithynia also joined themselves up with the anti-Seleucid symmachia created under the supervision of the Heracleots. All were members of the "Northern League", as this coalition is called by modern scholars....
... Mithridates I turned out to be a passive member of the coalition: he did not take part in the war waged by the League against Antigonus Gonatas in 280 BC (Memn. XII. 2). His name was absent from among those states and kings who signed a treaty between the Northern League and the Galatians in 278 BC in order to bring them to Asia Minor to oppose Antiochus I (Memn. XIX. 2). We do not find the Pontic king's name among the members of the alliance who were appointed by king Nicomedes I of Bithynia as guardians of his young children after his death around 255 BC (Memn. XXII. 1). The Pontic kingdom had evidently left the coalition, which at that time did not meet the needs of its policy.
After rebuffing Seleucid attacks, the kings of Pontus worked out two main lines in foreign policy — to strive to gain access to the coast of the Black Sea by conquering the greatest coastal Hellenic poleis, and to enlarge the state at the expense of the territories in the north-western sector of Asia Minor, which the Pontic rulers considered as their family possessions. First of all, they chose Phrygia and Mysia to be the aim of their irredentist foreign policy, because they were earlier ruled by Persian satraps, Ariobarzanes and Mithridates, ancestors of the Pontic rulers. Mithridates I of Pontus was greatly concerned with the appearance of Galatians in Asia Minor, who had settled down on land near Phrygia and the borders of the Pontic kingdom. He regarded them as a threat to his own interests in the region, since he had designs on both Hellespontine and Greater Phrygia.
Another cause for the change in the position of Pontus would appear to be the raprochement between Pergamum and the Seleucids. In 283 BC, the Pergamene ruler Philetaerus came under the power of Seleucus I (Paus. I. 10. 4) and, in early 270s BC, drew closer to Antiochus I (App. Syr. 63). For that reason the Pontic king had to change his policy: Phrygia and Mysia remained in the hands of the Seleucids, and there was a real threat that they would pass them over to Pergamum.... 2