Singidunum - meaning "Round Fort" was the original home to the Scordisci Tribe. Located in a fertile valley at the confluence of the Sava and Dunav (Danube) Rivers, it was an ideal Celtic settlement for nearly 600 years. Tin, Copper and Iron were mined in the nearby hills, and the valley was parceled out into farmlands. Sheep, Goats and Cattle were raised, along with barley, wheat and other grains. The Romans arrived around 40 BC and built a large fort to house their Fourth Flavian Legion. With the collapse of the Roman Empire, these lands were successively ruled by a number of different groups, making Beograd the cosmopolitan city it is today.