At first, they treated them with fairness but much more crue as the empire went on.
The Persians were mild rulers who let their conquered people keep their own language, religion, and laws.
usually teach them some Islam and make them free. as an example prophet Muhammad (PBUH) had some conquered people in a war and Muslims were uneducated and so he told them:who can teach reading and...
not very well.they killed all the men and inslaved all the rest
depends. if they broke the rules, they were treated harshly, but other than that, they were treated fine.