The second century AD was a time of upheaval for the region, and especially for Dura-Europos. In AD100, it was a fairly prosperous town of the western Arsacid empire, which already had significant economic and political contacts with the Roman-ruled Mediterranean world. By AD200, it was a Roman provincial city.
In 113 the Roman emperor Trajan invaded the Parthian empire. His armies won a battle before the walls of Dura, which seems then to have been treated as a Greek city 'liberated' from the Arsacids. Trajan's troops overran the whole of Iraq, but sustained resistance led to the Romans withdrawing after a few years.
Arsacid power was nominally restored over Europos, but it seems to have spent the next half-century in an uneasy no-mans-land between the empires until a new Roman invasion. The 160s marked a watershed in Dura's history. A serious earthquake was followed around 165 by permanent Roman annexation, and within a few years installation of a Roman garrison.
The House of Lysias and the Europaioi continued to dominate the civic landscape, but this was now a Roman provincial city, and they had less political autonomy under imperial rule--especially with influential military officers on the scene. The town was increasingly referred to as Dura rather than Europos in surviving documents. In the early third century, for reasons unknown the House of Lysias was removed from power. In AD 212 most imperial subjects were made full Roman citizens; the age of the Europaioi was over. The city also got a new constitution, gaining the honorific status of Roman colonia.
Dura changed physically too in this period. While a large area was taken over by the military as a base, the civil town began to acquire the street colonnades typical of Syrian cities under Rome. The garrison also built Roman-style baths near the main city gates. By the 220s Dura was becoming increasingly integrated as a Roman provincial city.
Image: Reconstruction of Dura around the AD230s, seen from the North with the sprawling Roman military base in the foreground, and the civil town beyond. Except for the small district nestling in the steep inner wadi near the River Gate, most of the city stood on the plateau about 40m (130ft) above the valley floor.