The situation within the Sassanid Empire continued to devolve after the bloody dispute between Narseh and Bahram. Well, over a dozen people had died in the search of the missing Princess, and the result was an outright declaration of war between her two brothers.
Naturally, the other candidates for the King of Kings took advantage of this, and begun using their influence to isolate their two rivals. Persian politics was a brutal, and bloody affair, and as a result, more and more men desiring the throne appeared out of the woodworks. Doing everything in their power to eliminate the other contenders.
Powerful nobleman, with no legitimate claim to the throne, began fabricating evidence that they were the rightful heir, all while Shapur assembled his forces, in a preparation to seize the throne once his two brothers had killed themselves while fighting over a woman. A woman who just so happened to be their sister.