Romans in Persia is related to the brief invasion and occupation of western and central areas of Parthia (modern-day Iran) by the Romans during their empire. Emperor Trajan was even temporarily able to nominate a king of western parts of Parthia, Parthamaspates, as ruler of a Roman "client state" in Parthia. Characteristics The Romans, having expanded into the eastern Mediterranean, came in contact with their historical rivals in the Middle East: the Parthians and Persians, whose respective empires occupied modern Iran and surrounding areas. The Iranian empires that faced the Romans had different names, related to the origin of the dynasties in control of their empires in different historical periods: first were the Medians (Media Atropatene), then Parthians and finally Sassanians. In 64 BC Pompey conquered the remaining Seleucid territories in Syria, extinguishing their state and advancing the Roman eastern frontier to the Euphrates, where Romans met for the first time the territory of the Parthians. Mark Antony, in his quest to avenge the battle of Carrhae defeat, conquered in 33 BC some areas of Atropatene (northern Iran) and Armenia but soon lost it: that was the first time that Romans occupied a Persian territory, even if temporarily. Furthermore, probably in 20 BC, Augustus is said to have nominated Ariobarzanes II, the son of Artavasdes, to be king of Media Atropatene, creating a semi-authonomous "vassal state" of Rome in what is now northwestern Iran. But soon, around 19 AD, The Parthians took again full control of Atropatene. Although warfare between the Romans and the Parthians/Sassanids lasted for seven centuries, the frontier remained largely stable in those centuries. A game of tug of war ensued: towns, fortifications, and provinces were continuously sacked, captured, destroyed, and traded. The line of stalemate shifted in the 2nd century AD with Trajan: it had run along the northern Euphrates until then. The new line ran northeast, across Mesopotamia to the northern Tigris. There were also several substantial shifts further north, in Armenia and the Caucasus. A new series of wars began in the 2nd century AD, during which the Romans consistently held the upper hand over Parthia. In 113 AD the Roman Emperor Trajan decided that the moment was ripe to resolve the "eastern question" once and for all time by the decisive defeat of Parthia and the annexation of Armenia: his conquests mark a deliberate change of the Roman Policy towards Parthia, and a