The Arab and mostly Berber immigrants who settled in the existing towns were drawn into broad contact with natives. Their immigration, though limited in numbers, introduced new agricultural and hydraulic technologies, new craft industries, and Levantine techniques of shipbuilding. They were accompanied by an Arabic-language culture that brought with it the higher learning and science of the classical and post-classical Levantine world. The Emir of Córdoba, Abd ar-Rahman I's policy of allowing the ethnic Arab politico-military elite to practise agriculture further encouraged economic and cultural contact and cohesion. Moreover, the interaction of foreign and native elements, fostered by intermarriage and contact in day-to-day commercial and social life rapidly stimulated acculturation between the two groups.