 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 (320-500CE).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.In 358 Shapur II was ready for his second series of wars against Rome, which met with much more success.