Kingdom of Armenia

State · 326 BCE – 646 CE · at its largest around 77 BCE

Kingdom of the Armenian Highlands ruled by the Orontid, Artaxiad and Arsacid dynasties, which became the first state to adopt Christianity in the early 4th century.

On its lands while it lasted

Ecbatana (c. 550 BCE – c. 1800 CE): Capital of Achaemenid Empire (550 BCE–330 BCE).
Campaigns of Alexander the Great (334–323 BCE): Alexander of Macedon crossed into Asia in 334 BCE, defeated Darius III at Issus and Gaugamela, conquered Egypt and the Persian Empire, and campaigned as far as the Indus valley before dying in Babylon in 323 BCE.
Artashat (c. 326 BCE): Capital of Kingdom of Armenia (326 BCE–428).
Van (c. 326 BCE): Capital of Kingdom of Armenia (326 BCE–428), Kingdom of Vaspurakan (911–1021).
Ardabil (c. 307 BCE): Capital of Atropatene (307 BCE–165 BCE).
Amasya (c. 281 BCE): Capital of Kingdom of Pontus (281 BCE–183 BCE).
Ctesiphon (c. 239 BCE – c. 637 CE): Capital of Parthian Empire (239 BCE–224).
Erbil (c. 63 BCE): Capital of Kingdom of Adiabene (63 BCE–370).
Battle of Carrhae (53 BCE): A Parthian army of horse archers and armoured cavalry destroyed a Roman army under Marcus Licinius Crassus near Harran, one of Rome's worst defeats.
Paul the Apostle (c. 5 CE – 64 CE): A Jewish-born missionary from Tarsus whose journeys and letters spread Christianity among non-Jews across the eastern Roman Empire.
Palmyra (c. 261–1929 CE): Capital of Palmyrene Empire (261–269).
Armenia adopts Christianity (c. 301 CE): Under King Tiridates III and Gregory the Illuminator, Armenia became the first state to adopt Christianity as its official religion, traditionally dated to 301.
Babylonian Talmud (c. 500 CE): Scholars of the Jewish academies of Babylonia compiled the Babylonian Talmud, which became the central text of rabbinic Judaism.
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.
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.