Query: When did the Sassanid Empire succeed the Parthian Empire in control of Iran?
Context: In the middle of the 2nd century BC, the Parthian Empire rose to become the main power in Iran, and the century-long geopolitical arch-rivalry between Romans and Parthians began, culminating in the Roman–Parthian Wars. The Parthian Empire continued as a feudal monarchy for nearly five centuries, until 224 CE, when it was succeeded by the Sassanid Empire. Together with their neighboring arch-rival, the Roman-Byzantines, they made up the world's two most dominant powers at the time, for over four centuries.