Rome never met an equal it couldn't eventually digest — except one. East of the Euphrates, a Persian dynasty resurrected an empire and spent four centuries fighting, bargaining with, and bankrupting the Romans in what may be history's longest great-power rivalry.
Ctesiphon ★ Edessa Hormozdgan Merv the Caucasus Greatest extent — stylized map 224 Ardashir, King of Kings 260 Valerian captured at Edessa 531 Khosrow I's golden age 602 War with Rome 636 Qadisiyyah 651 The fall Rise · zenith · fall The rise In 224, a Persian vassal king named Ardashir I defeated the last Parthian ruler at Hormozdgan and crowned himself “King of Kings.” The Parthians had ruled Iran for four centuries as a loose feudal confederacy; Ardashir built something harder — a centralized state with a standing army, a state religion, and an ideology: Persia restored, heir to the Achaemenids who had once ruled the known world.
