In the ancient Greco-Roman world, Sarmatia was a geographic region that encompassed the western Eurasian steppe. It was inhabited by the Sarmatians, an ancient Eastern Iranian equestrian nomadic people.
The Romans gave the name Sarmatia to the region which the ancient Greeks had formerly called Scythia because it had been inhabited by the Scythians. Beginning in the late 4th century BC the Sarmatians, a nomadic Iranian people related to the Eastern Iranic Scythians, moved from the east into the Pontic steppe, where they replaced the Scythians as the dominant power. Due to the Sarmatian incursion, "Sarmatia Europea" replaced "Scythia" as the name for the region.