The Sasanian Empire was founded by Ardashir I , after the fall of the Arsacid Empire and the defeat of the last Arsacid king , Artabanus V . At its greatest extent , the Sassanid Empire encompassed all of today 's Iran , Iraq , Eastern Arabia ( Bahrain , Kuwait , Oman , Qatif , Qatar , UAE ) , the Levant ( Syria , Lebanon , Palestine , Jordan , Israel ) , the Caucasus ( Armenia , Georgia , Azerbaijan , Dagestan ) , Egypt , parts of Turkey , much of Central Asia ( Afghanistan , Turkmenistan , Uzbekistan , Tajikistan ) , Yemen and Pakistan .
The Sassanid Empire 's traditional territory included all of today 's Iran , Iraq , Armenia , Afghanistan , eastern parts of Turkey , and parts of Syria , Pakistan , Caucasia , Central Asia and Arabia .