 The Sassanid era, encompassing the length of the Late Antiquity period, is considered to be one of the most important and influential historical periods in Iran.In many ways, the Sassanid period witnessed the highest achievement of Persian civilization and constituted the last great Iranian Empire before the Muslim conquest and adoption of Islam.Whereas the Romans were seen as the main aggressors against the Parthians, these roles were very much reversed by the Sassanids in their aggressiveness against the Romans and later the Byzantines.