The Seleucid Empire (/sÉȘËljuËsÉȘd/ sih-LEW-sid) was a Greek state in West Asia during the Hellenistic period. It was founded in 312Â BC by the Macedonian general Seleucus I Nicator, following the division of the Macedonian Empire founded by Alexander the Great, and ruled by the Seleucid dynasty until its annexation by the Roman Republic under Pompey in 63Â BC.
After receiving the Mesopotamian regions of Babylonia and Assyria in 321Â BC, Seleucus I began expanding his dominions to include the Near Eastern territories that encompass modern-day Iraq, Iran, Afghanistan, Syria, and Lebanon, all of which had been under Macedonian control after the fall of the former Achaemenid Empire. At the Seleucid Empire's height, it had consisted of territory that covered Anatolia, Persia, the Levant, Mesopotamia, and what are now modern Kuwait, Afghanistan, and parts of Turkmenistan.