Arsames I apparently takes control of Commagene, Sophene and Armenia in the year 260 BCE after the death of his grandfather Orontes III, king of Armenia, and his father Sames, king of Commagene.

Quite why they both die in the same year is not recorded, though it looks suspicious.

It is known the Seleucid Empire was always trying to overthrow the Armenian dynasties who still ruled the lands their forebears had in the time of the Achaemenid Empire.

Ziaelas of Bithynia finds refuge at the court of king Arsames, and upon the death of king Nicomedes I of Bithynia Ziaelas returns to take the kingdom in 254 BCE.