252-256 - Shapur I moves forward to the Eastern Roman Provinces.
c. 259 - Defeat and capture of Valerian by Shapur I.
c. 260 - 2nd foray of the Eastern Roman Provinces by Shapur I.
c. 261 - Odaenathus, the ruler of Palmyra, stops the triumphant Persian troops coming back home following the looting of Antioch, scores a notable victory while Shapur is absent and drives the Persians back across the Euphrates. He fails to take Ctesiphon and the Persians are victorious.
271 - Coronation of Hormizd I.
273 - Coronation of Bahram I.
274 or 277 - The execution of Mani by influential Zoroastrian high priest Kartir.
276 - Coronation of Bahram II.
An inscription of Kartir, with a relief of him holding the text
276 - The Kartir is chosen as extreme power of the Zoroastrian place of worship and victimizes the supporters of other believes; his engravings at Ka'ba-ye Zartosht, Naqsh-e Rajab, and Sar Mashhad (south of Kazerun) declare to prove his principles.
283 - Roman Emperor Carus seizes Mesopotamia and catches Ctesiphon, but his troops comes back his unexpected passing.
286 - Tiridates takes the Armenian throne and the Persians are discharged from there.
293 - Narseh overwhelms his competitors and triumphs to the Persian throne.
A small fragment of the Paikuli inscription; Middle Persian version
c. 294 - Narseh’s Paikuli inscription in Iraq next to the Persian frontier.
296 - Narseh raids Armenia, expels Tiridates, and quells the Romans.
297- Roman Emperor Galerius undoes Narseh. The Treaty of Nisibis compels Narseh to abandon Armenia and Mesopotamia.
c. 301 - The realm of Armenia is the first nation to accept Christianity as the state religion.
302 - Resignation of Narseh; Coronation of Hormizd II.
309 - Coronation of Shapur II.
325 - Shapur II falls upon Arab people and makes impregnable the empire’s frontiers.
338 - Shapur II retrieves the five regions gave in by Narseh to Rome.
363 - War between Julian and Persian troops follows his back off and demise; the surrendered territories and Nisibis are brought back to Persia.
376 - The armistice signed by Rome and Persia.
379 - Death of Shapur II and the accession of Ardashir II.
383 - Coronation of Shapur III.
399 - Coronation of Yazdegerd I, titled “the Sinner” owing to his efforts to control the influence of Zoroastrian clergy and his leniency towards other believes.
409 - Christian are allowed to publicly worship and to construct churches.[1]
Coin of Bahram V.
420 - Coronation of Bahram V (Bahram Gūr).
421 - Peace between Persia and Rome comes to an end.
422 - Bahram V triumphs in driving off an assault by the Hephthalites.
c. 425 - Bahram V brings in gypsies from India to amuse people according to the Shahnameh.
428 - Dissolution of Arsacid dynasty of Armenia. Establishment of Persian Armenia.
438 - Coronation of Yazdegerd II.
451 - Battle of Avarayr fought against the Christian Armenian rebels led by Vardan Mamikonian.
533 - End of conflict between Persia and Byzantine Empire (the one that started in 524).
541 - Lazic War commences between the Byzantines and the Sassanids for control over Lazica.
c. 554 - Procopius, Byzantine expert and observer to the battles between Khosrow I and Justinian I, which he writes in his De bello Persico (Latin tr., 1833), dies.
579 - Death of Khosrow I and the Coronation of Hormizd IV.
580 - Sassanids abolish the monarchy of the Kingdom of Iberia. Direct control through self-appointed governors commences.
588 - First Perso-Turkic War (with Göktürks) and their defeat at the hands of the Parthian general Bahrām Chobin.
590 - Hormizd IV is assassinated; Coronation of Khosrow II.
590 - Uprising of Bahrām Chobin and his seizure of the Persian throne.
591 - Overwhelming of Bahrām Chobin; he escapes to the Turks in Central Asia but is killed after a year. Khosrow II regains the throne with the help of the Byzantine Emperor Maurice.
602 - Mutiny against the Emperor Maurice led by Phocas. Climactic Byzantine–Sasanian War of 602–628 commences.
603 - Khosrow II’s invasion of Byzantium in revenge for the murder of Emperor Maurice and his relatives by the tyrant Phocas.
614 - Conquest of Jerusalem by Persian Shahanshah Khosrow II and Parthian general Shahrbaraz; relics of the True Cross are carried off to Ctesiphon, capital of the Sasanian Empire.
615 - Conquest of Asia Minor by Parthian general Shahin
618 - Conquest of Egypt by Parthian general Shahrbaraz
622 - Heraclius mounts a counter-offensive against the Sasanians.
626 - The Sassanids alongside the allied Avars and Slavs besiege the Byzantine capital, Constantinople
627 - Heraclius defeats the troops of the Sasanian Empire near Nineveh.
628 - Deposition, trial, and execution of Khosrow II by his son and successor Kavadh II (Shīrūya); peace concluded with Byzantine Empire.
628 - Murdering of many Sasanian princes by Kavadh II.
628 - Kavadh II dies.
628-635 - Weakening of the Sasanian dynasty due to a succession of ineffectual kings and queens including the queens Boran and Azarmidokht; chaotic situation prevails.
Coin of Yazdegerd III.
632 - Pond of Khumm event.
632 - The Prophet Moḥammad dies; there ensues a dispute over his succession.
632-634 - Abu Bakr’s caliphate.
633 - Yazdegerd III succeeds to the Persian throne.
634 - Umar elected caliph; he plans a successful invasion of Byzantine and Persian (Sasanian) lands.
634 - Persian victory over the Muslims at the Battle of the Bridge; Bahman Jadhuyah and Jalinus annihilate Arab force