Sassanid (Civ5)/Civilopedia

The last pre-Islamic Persian empire, the Sassanids ruled from 224 to 651 AD. Founded by Ardashir I, at its peak their empire encompassed all of modern Iraq, Iran, Afghanistan, Syria, the Caucusus, parts of Arabia and Pakistan, the Persian Gulf and part of Turkey. It rivaled Rome and Byzantium in power and influence during its first golden age under Bahram V (421-438 AD) and his immediate successors. The empire endured until a series of Arab invasions toppled the last emperor Yazdegerd III.
Myth and conflicting historical accounts shroud the fall of the Parthian empire and the rise of the Sassanid empire. Sassanid rule appears to have begun in Istakhr, capital of the province of Persis under the governorship of Ardashir, reputed a descendant of a line of priests. In the general collapse of Parthian rule, the ruthless Ardashir murdered his rivals (including his brothers), declared himself Shahanshah ("King of Kings"), and quelled rebellions in neighboring provinces. His son Shapur I continued the expansion, overrunning Armenia, Bactria, much of the fledgling Kushan empire and even mounted several campaigns against Rome.
From Shapur's death to Bahram V, the empire gradually grew to the east and south, although a series of inconclusive wars with Eastern Rome blocked Sassanid expansion to the west. Favoring more peaceful pursuits, Bahram V ushered in a golden age of literature, music, and sport. During the century following his death, however, his heirs were forced to spend their reigns fending off barbarian tribes, Byzantine and Arab invasions, and provincial revolts.
A second Sassanid golden age began under Kavadh I (488-531 AD). But incessant warfare with Byzantium drained the treasury and weakened Sassanid authority in the western provinces. Nonetheless, Sassanid armies managed to capture Jerusalem (614 AD), Alexandria (619) and the rest of Egypt by 621. However, the sudden expansion overextended their military, an overtaxed populace grew restless, and religious fervor gripped the Muslims to the south. In three decades, by 651, the Sassanid Empire was no more, replaced by the Abbasid Caliphate.