Mithridates I Conquers Media and Babylonia for Parthia
The Parthian kingdom becomes the Parthian Empire when its king takes the old Seleucid capital and the title Great King
Quick facts
- King
- Mithridates I
- Babylon occupied
- 13 April - 10 June 141 BCE
- Captured rival
- Demetrius II Nicator
- New title
- Great King
What happened
Mithridates I, who had already taken Media from the Seleucids in 148-147 BCE and added Elam and likely Persis soon after, occupied Babylonia itself between 13 April and 10 June 141 BCE. In July he captured the Seleucid capital Seleucia on the Tigris, and by October he had reached Uruk in southern Babylonia. When the Seleucid king Demetrius II Nicator tried to reclaim the lost territory, he was defeated and captured, a humiliation that confirmed the shift in power on the ground. Mithridates took the title of Great King following this conquest and adopted the surname Philhellene, or friend of the Greeks, despite his ongoing wars against the Greek-ruled Seleucid state.
Why it matters
Livius.org's assessment states plainly that it is not an exaggeration to call Mithridates the real founder of the Parthian Empire, since his conquests transformed a regional steppe kingdom into a state controlling the historic heartland of Mesopotamia and Iran together, the core of what would remain Parthian territory for the following three centuries.
How we know
The precise dates for the Babylonian campaign come from cuneiform astronomical diary tablets, which record contemporary political and military events alongside astronomical observations and give a rare month-by-month chronology for this campaign.
Sources
- Livius.org (Jona Lendering). Arsaces VI, Mithradates I the Great · Reputable sourcelivius.org · The domain "livius.org" is on our Reputable source registry. · Link is live and its text matches the event's key terms (Jul 2026)
- World History Encyclopedia. Parthia (Empire) · Reputable sourceworldhistory.org · The domain "worldhistory.org" is on our Reputable source registry. · Link is live and its text matches the event's key terms (Jul 2026)
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Part of a timelineAncient Persia27 events · Three empires in a row, Achaemenid, Parthian, and Sassanid, ran the largest state the ancient world had seen and left cuneiform, coinage, and a fire religion behindView all →