The question of the system of chronology used in Pontus in the 3rd-lst ее. ВС is still under discussion, the data of the sources being very contradictory. The author of the paper puts forward a hypothesis that originally in the Kingdom of Pontus they used a «royal era» made after the Seleucids' model; it began in 314 or 313 ВС and was connected with the flight of Mithridates I Ctistes, son of Ariobarzanes, to Paphlagonia, when Pontus began its de facto independent existence. The system seems to have been created by Mithridates I in 297/296 ВС when he assumed the royal title following the example of Zipoites of Bithynia. This may be proved by the Cappadocian coins dated with the year 200 and minted in the third year (98/97 ВС) of the rale of Ariarthes IX Eusebius, Son of Mithridates Eupator; the coins must have been issued in commemoration of the bicentenary of Mithridates Ctistes' coronation. Obviously, Ctistes' 36-year reign must have begun in 297/296 ВС; in which case his death followed in 261. Two well-known epigraphic monuments seem to be dated according to the «era of Kimiate-na»: a treaty between Pharnaces and Chersonesus (IOSPE I2 402) and a decree from Abonute-ichos in honour of Alkimos (under Mithridates V Euergetes). Their dates based on this system (158-157 and 154-153 ВС) are quite plausible, while other dates (according to some era beginning in 336 ВС and to the Bithynian royal era respectively) do not look convincing. The author rejects the widespread opinion of western scholars that in these monuments the Seleucid era was used. Analysing various narrative, epigraphic and numismatic sources, he comes to the conclusion that Mithridates IV Philopator Philadelphus was ruling within three or four years and should be fitted into the period mentioned above. It was not until 96/95 ВС that the Bithynian royal era began to be used in Pontus. Coins with dates according to this era appeared under Mithridates VI Eupator, which was connected with the death of the Bithynian king Nicomedes ГП Euergetes and was meant to show Eupator's political claims for submitting the neighbouring state.