The Sassanid Empire or Sassanian Dynasty  is the name used for the Iranian dynasty which lasted from 224 to 651 AD.

The Sassanid Empire, which succeeded the Parthian Empire, was recognized as one of the two great powers in Western Asia, alongside the Roman Empire and later the Byzantine Empire, for more than 400 years.

King of kings 
The Sassanid dynasty was founded by Ardashir I when he had defeated the last Parthian (Arsacid) king, Artabanus IV, and ended when the last Sassanid Shahanshah (King of Kings), Yazdegerd III (632–651), lost a 14-year struggle to drive out the early Arab Caliphate, the first of the Islamic empires.

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.

The Sassanid era is considered to be one of the most important and influential historical periods in Iran. In many ways the Sassanid period saw the highest achievement of Persian civilization, and constituted the last great Iranian Empire before the Muslim conquest and adoption of Islam.

Persia influenced Roman civilization considerably during the Sassanids' times,p109 and the Romans reserved for the Sassanid Persians alone the status of equals. The Roman Emperor wrote letters to the Persian Shahanshah, which were addressed to "my brother". Their cultural influence extended far beyond the empire's territorial borders, reaching as far as Western Europe, Africa, China and India, and played a prominent role in the formation of both European and Asiatic medieval art.

This influence carried forward to the early Islamic world. The dynasty's unique, aristocratic culture transformed the Islamic conquest of Iran into a Persian renaissance. Much of what later became known as Islamic culture, architecture, writing and other skills were borrowed mainly from the Sassanid Persians and propagated throughout the broader Muslim world.

Decline 
In the spring of 632, a grandson of Khosrau I, Yazdegerd III who had lived in hiding, ascended the throne. In that same year, the first raiders from the Arab tribes made their raids into Persian territory. They were united by Islam. Years of warfare had exhausted both the Byzantines and the Persians. The Sassanids were further weakened by economic decline, heavy taxation, religious unrest, rigid social stratification, the increasing power of the provincial landholders, and a rapid turnover of rulers. These factors made the Islamic conquest of Persia easier than it would have been in earlier times.

The Sassanids never mounted a truly effective resistance to the pressure applied by the Muslim conquests.

Sassanid Empire chronology 
226–241: Reign of Ardashir I:
 224–226: Overthrow of Parthian Empire.
 229–232: War with Rome.
 Zoroastrianism is revived as official religion.
 The collection of texts known as the Zend Avesta is assembled.

241–271: Reign of Shapur I:
 241–244: War with Rome.
 252–261: War with Rome. Capture of Roman emperor Valerian.
 215–271: Mani, founder of Manichaeism.

271–301: A period of dynastic struggles.

283: War with Rome. Romans sack Ctesiphon.

296-8: War with Rome. Persia cedes five provinces east of the Tigris to Rome.

309–379: Reign of Shapur II "the Great":
 337–350: First war with Rome with relatively little success.
 359–363: Second war with Rome. Rome returns trans-Tigris provinces and cedes Nisibis and Singara to Persia.

387: Armenia partitioned into Roman and Persian zones.

399–420: Reign of Yazdegerd I "the Sinner":
 409: Christians are permitted to publicly worship and to build churches.
 416–420: Persecution of Christians as Yazdegerd revokes his earlier order.

420–438: Reign of Bahram V:
 420–422: War with Rome.
 424: Council of Dad-Ishu declares the Eastern Church independent of Constantinople.
 428: Persian zone of Armenia annexed to Sassanid Empire.

438–457: Reign of Yazdegerd II:
 441: War with Rome.
 449-451: Armenian revolt.

482-3: Armenian and Iberian revolt.

483: Edict of Toleration granted to Christians.

484: Peroz I defeated and killed by Hephthalites.

491: Armenian revolt. Armenian Church repudiates the Council of Chalcedon:
 Nestorian Christianity becomes dominant Christian sect in Sassanid Empire.

502-506: War with Constantinople.

526-532: War with Constantinople.

531–579: Reign of Khosrau I, "with the immortal soul" (Anushirvan)

540–562: War with Constantinople.

572-591: War with Constantinople. Persia cedes much of Armenia and Iberia to Constantinople.

590–628: Reign of Khosrau II

603–628: War with Byzantium. Persia occupies Byzantine Mesopotamia, Syria, Palestine, Egypt and the Transcaucasus, before being driven to withdraw to pre-war frontiers by Byzantine counter-offensive.

610: Arabs defeat a Sassanid army at Dhu-Qar.

626: Unsuccessful siege of Constantinople by Avars and Persians.

627: Byzantine Emperor Heraclius invades Assyria and Mesopotamia. Decisive defeat of Persian forces at the battle of Nineveh.

628–632: Chaotic period of multiple rulers.

632–642: Reign of Yazdegerd III.

636: Decisive Sassanid defeat at the Battle of al-Qadisiyyah during the Islamic conquest of Persia.

642: Final victory of Arabs when Persian army destroyed at Nahavand (Nehavand).

651: Last Sassanid ruler Yazdegerd III murdered at Merv, present-day Turkmenistan, ending the dynasty. His son Pirooz and many others went into exile in China.

Notes

References 
 Iranologie History of Iran Chapter V: Sasanians 
 Iran Chamber Society (History of Iran) 
 Livius articles on ancient Persia 
 Richard Frye "The History of Ancient Iran"
 Iransaga: Persian arts through the centuries
  Christianity in Ancient Iran: Aba & The Church in Persia
 Sasanika: the History and Culture of Sasanians

Other websites 
 Sasanian rock reliefs, Photos from Iran, Livius .
 Sasanian Dynasty entry in the Encyclopædia Iranica
 ECAI.org The Near East in Late Antiquity: The Sasanian Empire 
 The Art of Sassanians
 Sassanid crowns 
 Sassanid coins 
 Sassanid textile 
 Islamic Metalwork The continuation of Sassanid Art
 A Review of Sassanid Images and Inscriptions
 Sasanians in Africa in Transoxiana 4.
 Ctesiphon; The capital of the Parthian and the Sassanid empires, By: Jona Lendering
 Islamic Conquest of Persia
 Pirooz in China, By Frank Wong
 The Sassanian Empire  BBC – Radio 4 In Our Time programme (available as .ram file)
 The Sassanian Empire: Further Reading

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Former countries in the Middle East
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651 disestablishments
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