between the Romans and Parthians in the northwest; in the east, the Kushan and Turan and probably Merv Desert rulers surrendered to Ardashir's empire; and in the southwest, the northern part of "Arabic shores of the Persian Gulf"were taken by war. War with Rome According to the information collected from Latin and Greek sources, the first clash between the "newborn Sasanian power" in its west borders with Rome occurred by the Persians' attack on the regions held by Rome in Northern Mesopotamia on Ardashir's era, 230. Ardashir besieged Nusaybin, which was one of the two fortresses of Roman defense system in Mesopotamia -the other being Harran, but was not able to take it; the Sasanian riders' assault was pulled to other Syrian regions and Cappadocia and they invaded it. After the Romans' unfruitful attempt to make peace with Ardashir, Severus Alexander eventually decided to oppose the Persians unwillingly and reluctantly in 232. The Roman forces led by Alexander attacked Armenia by one military column and the south by two columns. Although there is no accurate information about the details of the events, it is known that the Romans achieved some victories in the north (Armenia); but the troops sent to Southern Mesopotamia did not achieve anything. In any case, "the first war test between the Sasanians and Romans" ended without any positive result for the Romans; though Alexander held a celebration in Rome for his "victory" and the war has been viewed as a victory in some Roman writings due to preserving the past borders of the Roman empire and Alexander appeared as a victor in Rome. In the war, many casualties were inflicted upon the two armies. In subsequent Arabic-Persian sources, there has been no mention of the war; the cause of not mentioning might have been Ardashir considering the incident shameful. Although no peace treaty was signed, the eastern Roman borders were not attacked by the Sasanians in the next years. It might have been more important for the Romans to attach Hatra to their fortresses of the border defense system. The people of Hatra knew that their relative autonomy, which became possible at the late Parthian era due to the weakness of the central government, was under the threat of the policies announced by the Sasanians. The foreign policy of the new Persian rulers was to proceed to the Occident and that was probably in order to