From the 8th century BC, Phoenicians founded several cities and strongholds on strategic points in the south and west of Sardinia, often peninsulas or islands near estuaries, easy to defend and natural harbours, such as Tharros, Bithia, Sulci, Nora and Caralis (Cagliari). The north, the eastern coast and the interior of the island continued to be dominated by the indigenous Nuragic civilization, whose relations with the Sardo-Punic cities were mixed, including both trade and military conflict. Intermarriage and cultural mixing took place on a large scale. The inhabitants of the Sardo-Punic cities were a mixture of Phoenician and Nuragic stock, with the latter forming the majority of the population. Sardinia had a special position because it was central in the Western Mediterranean between Carthage, Spain, the river Rhône and the Etruscan civilization area. The mining area of Iglesiente was important for the metals lead and zinc.