Sarmatian steppe people that migrated westward c. 200 BC from Central Asia to the Ukrainian steppe, then by c. 44 BC into the Danube-Tisza plain (modern Hungary/Serbia), where they took up a semi-sedentary lifestyle as a Roman buffer/client people on the Dacian frontier.
Fought on Rome's side in the Dacian Wars, then against Rome in the Marcomannic Wars (169-175 AD), after which Marcus Aurelius defeated and imposed harsh terms on them; continued Iazygian presence in the Pannonian plain after 175 AD is plausible but not verified in the sources checked here.
Osprey-format survey covering the Iazyges among the western Sarmatian groups on the Danube frontier.
Foundational scholarly survey of Sarmatian archaeology and history, including the Iazyges.