The Kaysite dynasty was a Muslim Arab dynasty that ruled an amirate centered in Manzikert from c. 860 until 964. Their state was the most powerful Arab amirate in Armenia after the collapse of the ostikanate of Arminiya in the late 9th century.
The Kaysites were members of the Banu Sulaym tribe, which had settled in the Jazira after the Muslim conquest. By the reign of the Abbasid Caliph Harun al-Rashid (786–809) the Sulaym had probably advanced into the region around Lake Van. Manzikert and the surrounding regions, however, weren't in Arab hands until the rebellion of the Armenians against the Arab ostikan (governor) in 850. This rebellion prompted the caliph al-Mutawakkil (842–861) to send the Turk Bugha al-Kabir into Armenia with an army.
Bugha defeated the leading princes of Armenia and took several prisoner, before departing the country in 855. His defeat of the Armenian princes had enabled the Sulaym Arabs to surge into the area of Apahunik', which included the city of Manzikert. By 860 the region had fallen under the control of the first Kaysite amir, Abu'l-Ward.
For most their existence of the Kaysite state, the amirs recognized their stronger neighbors as suzerains, though often these declarations were only nominal and in effect the Kaysites were independent.
When Abu'l-Ward took control of Apahunik', the ostikanate of Arminiya was still extant. As a result, Abu'l-Ward, as with all the other Arab and Armenian rulers in Armenia, were subject to the caliph's ostikans. The ostikans served as protectors of the Kaysites, and relations between them were overall friendly. When a pan-Arab coalition led by the ostikans against the increasingly powerful Christian princes of Armenia in the late 870s was formed, Abu'l-Ward was one of its most powerful members.
The ultimate failure of the coalition against the Christian Armenians foreshadowed the end of the Arminiyan ostikanate in the next decade. In place of the ostikans, in 885 the caliph al-Mu'tamid (870–892) sent a crown to the Bagratid prince Ashot I, thereby restoring the Kingdom of Armenia. This move made the Kaysites subject to Ashot, who Abu'l-Ward was on bad terms with. By the late 890s the reigns of both Ashot and Abu'l-Ward were at an end; Ashot was succeeded by his son Smbat I (890–912) while Abu'l-Ward's three grandsons eventually assumed power. When Smbat I fell into difficulties early in his reign Abu'l-Ward's grandsons revolted against his authority but were defeated in battle. They were forced to resume paying tribute to the king and to send hostages.