The Sarmatians were a large Iranian confederation that existed in classical antiquity, flourishing from about the 5th century BC to the 4th century AD. Originating in the central parts of the Eurasian Steppe, they were part of the wider Scythian cultures. They started migrating westward around the 4th and 3rd centuries BC and at their greatest extent ranged from the Vistula river to the Volga. Sarmatia covered modern day central and south-eastern Ukraine, southern Russia, the Volga and South-Ural regions, as well as areas of the north-eastern Balkans and around Moldova. In the 1st century AD, the Sarmatians began encroaching upon the Roman Empire in alliance with Germanic tribes until the 3rd century AD when their dominance of the Pontic Steppe was broken by the Germanic Goths. With the Hunnic invasions of the 4th century, many Sarmatians joined the Goths and other Germanic tribes (Vandals) in the settlement of the Western Roman Empire.