According to the historian Stephen H. Rapp in the third edition of the Encyclopaedia of Islam:[2]Early Arabs followed Sāsānian, Parthian Arsacid, and ultimately Achaemenid practice by organising most of southern Caucasia into a large regional zone called Armīniya (cf.

[5] Armenian histories report that the Arabs first arrived in 642, penetrating the central region of Ayrarat, and sacked Dvin, returning with over 35,000 captives.

[6] In 643, the Arabs invaded again from the direction of Arran, ravaged Ayrarat and reached Iberia, but were defeated in battle by the Armenian leader Theodore Rshtuni and forced back.

[6] Emperor Constans then campaigned in person in Armenia, restoring Byzantine rule, but soon after his departure in early 654, the Arabs invaded the country.

[6] However, with the outbreak of the First Muslim Civil War in 657, effective Arab authority in the country ceased, and Mamikonian returned to Byzantine overlordship almost immediately.

Armenia was considered conquered land by the Arabs but enjoyed de facto autonomy, regulated by the treaty signed between Rhstuni and Mu'awiya.

[10][11] For much of the remaining Umayyad period, Arminiya was usually grouped with Arran and the Jazira (Upper Mesopotamia) under a single governor into an ad hoc super-province.

[12] Arminiya was governed by an emir or wali headquartered at Dvin, whose role however was limited to defence and the collection of taxes: the country was largely run by the local princes - the nakharars.

Acting as the head of the other princes, the ishkhanac' ishkhan was answerable to the Arab governor, being responsible for the collection of the taxes owed to the caliphal government and the raising of military forces when requested.

This was followed by Caliph al-Mansur revoking the privileges and abolishing the subsidies paid to the various Armenian princes (the nakharars) and imposing harsher taxation, leading to the outbreak of another major rebellion in 774.

At the same time, the power vacuum left by the destruction of so many nakharar clans was filled by two other great families, the Artsruni in the south (Vaspurakan) and the Bagratuni in the north.