Arabs first established themselves in the Caucasus in the eighth century, during the Islamic conquests of the Middle East. The process of shrinking of the Caliphate in the tenth century was followed by the establishment of several Arab-ruled principalities in the region, chiefly the principality of Shirvan (most of present-day Azerbaijan and southeast part of Dagestan) ruled by the Mazyadid dynasty. As the rulers of Shirvan (known as Shirvanshahs) spread their control over much of the Southeast Caucasus and at the same time found themselves more and more isolated from the Arab world, they were undergoing gradual Persianisation. Arab personal names of the Shirvanshahs gave way to Persian ones, members of the ruling dynasty were claiming Ancient Persian descent (possibly having intermarried