The history of Slovenj Gradec is closely tied to Stari Trg, a suburb southwest of the Old Town where there was a Roman settlement called Colatio that existed from the 1st to the 3rd centuries (though there is no trace of it now). At that time an important Roman road from Celeia (Celje) to Virunum (near Klagenfurt in Austria) passed through Colatio. Slovenj Gradec was an important trade centre in the Middle Ages and minted its own coins. Later it became a cultural and artistic centre, with many artisans and craft guilds. Among the prominent Habsburg nobles based in Slovenj Gradec over the centuries were members of the Windisch-Grätz family, a variant of the German name for the town (Windisch Graz).