Throughout antiquity (400 BC–500 AD), many distinct ancient ethnic groups populated the territory of present-day Poland, notably Celtic, Scythian, Germanic, Sarmatian, Slavic and Baltic tribes. Furthermore, archaeological findings confirmed the presence of the Roman Legions. These were most likely expeditionary missions sent out to protect amber trade along the Amber Road. The Polish tribes emerged in the course of the Migration Period in the mid-6th century. These were predominantly West Slavic and Lechitic in origin, but also comprised assimilated ethnic groups who inhabited the area for thousands of years. The earlier tribal communities may have been associated with the ancient Wielbark and Przeworsk cultures.