In the first half of the millennium, Celtic tribes across the Pyrenees mix with the Iberians to form the Celtiberians, a large ethnographic group in the north central part of the peninsula. In the south, Iberian culture is influenced by civilizations of the eastern Mediterranean through trade and colonies established first by the Phoenicians, and later the Greeks, Carthaginians, and Romans. In the last two decades of the third century B.C., Rome and Carthage wage a bitter struggle for control of the peninsula’s strategic cities and rich silver mines. Rome eventually becomes the dominant power, although it takes nearly 200 years to pacify tribes that resist imperialist control.