"Orodes I (Persian: ارد يکم‎) ruled the Parthian Empire from 87/80 to 75 BC in succession to Gotarzes I. He reigned during the "Parthian Dark Age," which was a period of internal turmoil and civil war for the Parthian Empire. Coins bearing Orodes´ likeness were issued from the Median mints of the cities of Ecbatana and Rhagae.
The history of Parthia is quite obscure during this period, but Orodes´ reign seems to have ended, as it had begun, in civil war with an unknown claimant. The name of his successor, Arsaces XVI, is also unknown, and it is only with the beginning of the reign of Sanatruces, c. 77 BC, that the line of Parthian rulers can again be reliably traced." - (en.wikipedia.org 06.02.2020)
