When the decisive battle of the Yarmuk in 636 AD gavethe Muslim Arabs control of Syria, they gained aland that had been Roman for 700 years. Yet in thememory of most of its inhabitants, their recentsubjection to the Sassanian Persians would have beenfresh and even dominant. The forces of Chosroes II,which had controlled Syria for a generation, hadonly been withdrawn in 630. Anyone who had reachedadulthood by the time the Arabs arrived had alreadyexperienced the Persian occupation; many were bornor raised during it. This period of Persian rule,which lasted twenty years or more in Syria,Mesopotamia and Armenia, fifteen in Palestine andten in Egypt, may have played a major role inaccustoming the locals to non-Roman rule, or mayhave had violently disruptive effects thatfacilitated the subsequent Arab conquest. So far,the period has been poorly known and never studiedas a whole, allowing many theories to be projectedupon it. For the most part, historians andespecially archaeologists have assigned to thePersians a highly negative and destructive role.