Research on the tumuli tells us that tribes underwent stratification, and that, probably, tribal chiefs existed. Some tumuli did not differ from others only by their place and size, but also by the objects put in them. They were full of homemade, but also imported weapons, and other items made of gold and silver. This group was developed also in Herzegovina, Metohia and northern Albania. Finds from tumuli provide evidence of extensive trade with the Greeks.
Roads lead through Macedonia and from the eastern Adriatic after the Greek colonization.
Illyrians inhabited the western parts of the Balkans, and the Glasinac culture could be ascribed to them, while west of the Iskera and Struma rivers lived Tracians. Between them were Triballis and Dardanians, which ancient writers identified with the Thracians and Illyrians. Fibulae, decorative and functional pins, were widely used in the Iron Age. Subsequently, arched shapes appeared with starry adornments, stylized snakeheads etc.