There is little or no information regarding Baku in medieval sources until the 10th century. The earliest numismatic evidence found in the city is an Abbasid coin dating from the 8th century AD. At that time Baku was a domain of the Arab Caliphate and later of Shirvanshahs. During this period, they frequently came under assault of the Khazars and (starting from the 10th century) the Rus. Shirvanshah Akhsitan I built a navy in Baku and successfully repelled another Rus assault in 1170. After a devastating earthquake struck Shamakhy, the capital of Shirvan, Shirvanshah's court moved to Baku in 1191. A mint was put into operation.