In 650–51, the Sasanian emperor Yazdegerd III made Estakhr, which is approximately 8 km northeast of Persepolis, the new capital of Sassanian Empire and tried to plan an organized resistance against the Arabs; and after some time he went to Gor, but Estakhr failed to put up a strong resistance. The Muslim leader Salman the Persian, who had knowledge of Sasanian tactics, instructed the Muslim forces to dig a large trench in the path of the Sasanian forces.[1] This strategy prevented the Sasanians to from succeeding in the battle.