The Banner of Kaviyan was a flag created by Persian magi to ensure victory for its armies. Spells were cast while the blue silk banner was being woven and and again when the emblem of the sun and moon were embroidered with gold and silver threads. So long as an army displayed the banner, it could not be defeated. The army of the King of Kings Khusro, led by marshal Shahr Baraz succeeded in reconquering Palestine, Egypt, and Asia Minor, and dreamed of sacking Constantinople.
With these victories, Khusro considered the Banner of Kaviyan to be a treasure too valuable to risk in battle. He therefore had it sent to Ctesiphon for safe-keeping. It was hidden away in the Imperial Palace with only a few trusted officials knowing where in the elaborate structure it was placed. This was to prevent rebellion as possession of the banner would leave the rebel army invincible.
But without the banner, the Persian victories were reversed and the Romans went on the offensive. Khusro feared to enter Ctesiphon since it was prophesized that he would be destroyed if he did and so fought on without the banner. However, he continued to lose ground and so eventually went to Ctesiphon to retrieve the banner. But none of the officials who knew where it was hidden remained and after desperate searching it was not found. Khusro was forced to flee but was eventually captured by his son and killed by slow torture.
The Banner of Kaviyan remained undiscovered and and Persia collapsed from Roman attacks, civil war and finally the invasion and conquest by the Arabs. The Arabs sacked and burned Ctesiphon but they too failed to find the banner. Generations later, Shahin set out on a quest to find the banner after learning of it from his great-grandfather.