The basic policy of the Umayyads, dictated by necessity, was the preservation of the existing administrative structure in the provinces. Umayyad practice thus naturally absorbed many concepts and institutions of foreign origion.
Such adoption of existing administrative machinery naturally opened the door to a wider reception of foreign elements in the substantive law proper.
The task of the Umayyads had been to establish a practical system of legal administration, not a science of jurisprudence.
In the different provinces of Islam flourished many school of law. The most important of them where the medinian and kufian.