Although victorious in battle, Shapur II could make no further progress with Nisibis un-taken. At the same time he was attacked in the east by Scythian Massagetae and other Central Asia nomads. He had to break off the war with the Romans and arrange a hasty truce in order to pay attention to the east (350). Roughly around this time the Hunnic tribes, most likely the Kidarites, whose king was Grumbates, make an appearance as an encroaching threat upon Sasanian territory as well as a menace to the Gupta Empire (320-500 CE). After a prolonged struggle (353–358) they were forced to conclude a peace, and Grumbates agreed to enlist his light cavalrymen into the Persian army and accompany Shapur II in renewed war against the Romans, particularly participating in the Siege of Amida in 359.