Your rather harsh on them. The Sassanids spent the last three centuries of their reign in an almost constant state of war with the Byzantines. They beat Belisarius and other Byzantine commanders on a number of occasions. They manage to grab all of Asia Minor and Egypt from the Byzantines and put Constantinople under siege.Originally Posted by CaesarAugustus
When they fell the Byzantines had just mounted a counterinvasion into their territory, which had devastated parts of the Sassanid Empire. On top of that they had dynastic struggles with pretenders to the throne and the aristocracy trying to curtail the King of kings power in favor of their own intrests.
They actually beat back the first arab invasion but couldn't keep fighting with the nobles meddling in the governance of the state. Even after their capital fell after a long siege parts of Persia kept resisting the arabs for decades before being conquered.
One of the reasons they converted to Islam was that the arab conquerors imposed a "faith tax" on all non believers. Basically anyone who wasn't a moslem.
The great byzantine emperor did not fare any better against the arabs. He got beaten in Syria and lost Egypt, Africa and Palestine.
Both the Sassanids and the Byzantines had kept warring for centuries and were exhausted and almost broke. Small wonder that a bunch of religious fanatics on a holy war could beat them. The Byzantines were lucky that the arabs focused on the Sassanids rather than them. If they hadn't, I doubt in their weakened state they could have managed to survive any better.
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