The last great Persian empire before Islam, ruling Iran and Mesopotamia from 224 to 651 CE. Founded by Ardashir I, who overthrew the Parthians, the Sasanians made Zoroastrianism a state religion served by a powerful priesthood, built a capital at Ctesiphon, and fought Rome and then the Byzantine Empire for four centuries over the Near East. They reached their height under Khosrow I and Khosrow II, exhausted themselves in a final ruinous war with Byzantium, and were conquered by Arab Muslim armies in the 630s and 640s; the last shah, Yazdegerd III, was killed in 651. Persian administrative, artistic, and courtly forms then deeply shaped Islamic civilization.
When an Arab army camped before the Persian capital in 637, the soldiers found a palace they could barely comprehend. The great vaulted hall at Ctesiphon rose higher than anything they had built, its brick arch springing without a single supporting column. Inside, by later tradition, they found a carpet woven to picture a garden, its flowers and streams sewn in gold thread and gemstones. It was kept to remind the king of spring in the depth of winter. They cut it into pieces and shared it out as plunder. The empire that made such things had stood for four centuries and faced Rome and then Byzantium as its great rival. Within a generation it was gone, its last king hunted down and killed near a distant mill. Yet the Arabs who destroyed it would spend the next several centuries learning to rule, to build, and to imagine kingship the way the Persians had.