The history of the coinage of the Pontic Kingdom probably began during reign of Mithridates II of the Kingdom of Pontus. Early Pontic coinage imitated coinage with Alexander the Great's portraits. Later coinage is well known for its high decree of realism in portraits of the Pontic kings who were proud of their Iranian ancestry. Pontic coin portraitry developed isolated from wider Hellenistic tradition. However, Mithridates V and his son Mithridates VI partially abandoned oriental influences in the coin portraitry. Pontic mints experimented with new materials for coinage. Pure copper and brass were used in mints during reign of Mithridates VI. His brass coinage are the earliest known coins made from brass. His rule and wars resulted in a wide expansion in number of mints and struck coinage. Earlier Pontic coinage attributable to prior rulers is very rare. Pontic coinage managed to gain a wide acceptance within eastern Mediterranean region. Evolution of Pontic coinage Prior to the Kingdom of Pontus, the Pontic region had autonomous, mostly coastal, cities with Greek background. Cities with mints were almost exclusively Greek colonies. It is likely that the first coinage was struck during Mithridates II's reign. His reign is assumed to have lasted from 255 BC to 220 BC. The first Pontic coinage mimicked other coinage with Alexander the Great's image on them. Mithridates III had issued substantial amount of silver coinage by the end of his reign. He was also the first Pontic ruler to have a coin with his own portrait. Before Mithridates VI Pontic coinage is very rare. This has complicated studies of royal Pontic coinage. However, chronology of the Pontic coinage is well known from research. For instance, Mithridates VI dated most of his coins by the Bithynian year and by month. There was a distinction between royal and city coinage. Royal coinage was struck on gold and silver. They also had king's image and name on them. Coinage produced by cities were made from bronze and had name of the city on reverse side of the coin. Coinage struck autonomously by cities was discontinued for a time, as the cities lost their autonomy under reign of Pharnakes I. Mithridates VI restored privilege of cities to have their own coinage, but he retained some control, as can be deducted from standardization of local coinage. Pontic coinage has very fine portraits of their kings. Only Greco-Bactrian coinage is minted in such