Sasanian Empire

State · 215–643 CE · at its largest around 623 CE

Zoroastrian kings of the second great Persian empire carved their triumphs into cliffs at Naqsh-e Rostam and built the vast arched palace at Ctesiphon. Their court culture of silverwork, silk, polo and chess shaped Byzantium and the Islamic world that followed.

On its lands while it lasted

Uruk (c. 5,000 BCE – c. 700 CE): Sumerian city on the Euphrates that by about 3100 BCE was probably the largest city in the world, centre of the first urban civilization.
Sogdians (c. 500 BCE – c. 900 CE): Iranian people of the Zeravshan valley around Samarkand and Bukhara whose merchants dominated trade along the Silk Roads, especially between the 4th and 8th centuries.
Ctesiphon (c. 239 BCE – c. 637 CE): Capital of Parthian Empire (239 BCE–224).
Silk Road (c. 130 BCE – c. 1450 CE): A network of overland caravan routes linking China with Central Asia, Persia and the Mediterranean, along which silk, spices, horses, religions, technologies and diseases travelled for more than 1,500 years.
Constantine the Great (c. 272 CE – 337 CE): First Roman emperor to convert to Christianity; he legalised the faith and refounded Byzantium as Constantinople.
First Council of Nicaea (325 CE): The first ecumenical council of the Christian church, convened by Constantine the Great, condemned Arianism and adopted the Nicene Creed.
Constantinople (330 CE): Constantine the Great refounded Byzantium as Constantinople, capital of the Roman Empire in the east; as Istanbul it later became the Ottoman capital.
Justinian I (482 CE – 565 CE): Byzantine emperor who reconquered Italy and North Africa, codified Roman law and built the Hagia Sophia.
Arabic script (512 CE): Arabic writing grew out of the Nabataean alphabet; the Zabad inscription of 512 is among its earliest dated examples, and with the Quran the script spread from Spain to Indonesia.
Hagia Sophia (537 CE): Great church of Constantinople built under Justinian I, whose vast dome made it the largest cathedral in the world for nearly a thousand years.
Plague of Justinian (541–549 CE): First recorded outbreak of bubonic plague in the Mediterranean world; it struck Constantinople in 542 and killed a large share of the population.
Muhammad (c. 570 CE – 632 CE): The prophet of Islam, born in Mecca, who united much of Arabia under the new faith before his death in Medina.
First revelation of the Quran (c. 610 CE): According to Islamic tradition, Muhammad received his first revelation in the cave of Hira near Mecca in 610, beginning the Quran and the religion of Islam.
The Hijra (622 CE): Muhammad and his followers migrated from Mecca to Medina, where he established the first Muslim community; the year marks the start of the Islamic calendar.
Battle of the Yarmuk (636 CE): Arab Muslim armies decisively defeated the Byzantine army near the Yarmuk River, opening the Levant to the Muslim conquest.