c. 520 BC – Persian armies under Darius I conquer much of Central Asia (inc. Ferghana, Sogdiana, and Chorasmia).
Central Asia – Alexander the Great conquers Bactria, Margiana, Sogdiana, and Ferghana in a multi-year campaign.
Afghanistan – The Seleucids and Mauryans sign a treaty, which gives control over Arachosia & Gedrosia (most of modern Afghanistan & Pakistan) to the Mauryans.
c. 248 BC
Central Asia – The Satraps of Bactria & Parthia break away from the Seleucid Empire and form their own kingdoms.
c. 244 BC
Parthia – A Saka tribe called the Parni invade Parthia, killing Andragoras. The Parni adopt the name of their new land and crown their leader as King Arsaces I.
c. 230 BC
Bactria – King Diodotus II is overthrown by Euthydemus I, beginning the “Euthydemid dynasty”.
Parthia – Seleucid king Antiochus III forces King Arsaces to recognize Seleucid authority.
Bactria – Seleucid king Antiochus III defeats King Euthydemus but is unable to take the capital city (Bactra). Peace is concluded when Euthydemus accepts Seleucid authority.
Mongolia – Xiongnu tribes are united by Maotun to form the Xiongnu Khanate.
India – The Mauryan dynasty is overthrown by the Sunga dynasty when a minister named Pushyamitra Sunga assassinates the last Mauryan emperor.
Afghanistan – Greco-Bactrian king Demetrius I invades Sunga lands in retaliation for the overthrow of the Mauryans. Demetrius seizes Arachosia, Gedrosia, Sindh, and the Punjab region.
Mongolia – The Xiongnu destroy the Tocharian (Yuezhi) federation in Kansu, and some Tochari flee westward towards Wusun and Dzungaria.
Dzungaria – Northern Saka (Sai Wang) tribes are conquered by the Tochari. Some of the Sakas escape and flee south to settle in Ki-pin (near Kashmir).
Iran – Mithradates I becomes King of Parthia after the death of Phraates I.
Bactria – Civil war splits Greco-Bactria when King Antimachus is overthrown by a general named Eucratides. The Euthydemids retreat to India and become known as the “Indo-Greeks”.
Iran – Parthian forces seize Merv & Herat from the Eucratidians during the Greco-Bactrian civil war.
Afghanistan – Menander becomes king of the (Euthydemid) Indo-Greeks.
Dzungaria – The Tochari are defeated by the Wusun (Issedones) and forced to flee to the southeast through Ferghana (Dayuan).
Transoxiana – The Tochari defeat the Western Saka tribes (probably descents of the Massagetae). The Western Sakas flee to the south and west, invading Parthia and Greco-Bactria.
Bactria – Western Sakas defeat King Eucratides II of Greco-Bactria and destroy the city of Alexandria-on-the-Oxus (modern Ai-Khanoum).
Bactria – The Tochari defeat King Heliocles I and destroy the last Greek kingdom in Bactria. The Eucratidians flee and set up a new kingdom in Kabul.
Iran – Saka mercenaries rebel & destroy a Parthian army, killing King Phraates II. His uncle is crowned as Artabanus II.
Central Asia – Chinese envoy Zhang Qian travels to Tochari lands in Bactria, leaving written records of the lands immediately after the Tochari conquest.
Iran – Parthian king Artabanus II is killed fighting a new wave of Saka tribes. He is succeeded by Mithradates II.
Central Asia – A Chinese army under Ban Chao reaches the Black Sea, marking the westernmost expansion of Han authority.
Afghanistan – Parthian forces defeat the Eucratidians and seize control over Arachosia (renamed Sakastan). A Partho-Sakan clan called Suren becomes prominent in the region.
Mongolia – Dingling and Wuhuan tribes rebel against the Xiongnu.
Afghanistan – Indo-Parthian forces seize Gandhara from the Indo-Greeks.
India – Azes I becomes King of the Saka.
Mongolia – Xiongnu Empire breaks into Eastern & Western Khanates.
Dzungaria – Northern Xiongu Khan Zizhou is killed by Han armies, ending the Western Xiongnu Khanate.
Mongolia – The Eastern Xiongnu rebuild their empire in Mongolia.