Caucasian Albania (Aghbania, Aghvania) (or ‘Arran' as it is described In Arab sources) was destroyed by the Arab conquests of the seventh century; the territory of the present-day Republic of Azerbaijan roughly corresponds to the ancient Caucasian Albania. Twenty six languages were spoken in Albania and it had its own kings.
Caucasian Albania became Christianized at approximately the same time as was Armenia; Movses Dasxuranc'i places this event in the reign of King Urnayr in the mid-4th century CE, and states that St. Gregory, founder of the Armenian national church, was responsible for the monarch's baptism. The Monophysite Albanian church remained separate from the Armenian one till the end of the 7th century CE, when the two were united under stimulus from the Arabs. Until well into medieval Islamic times, Muslims must have been only a minority in Arran; Moqaddasi, p. 376, writing towards the end of the 4th/10th century, describes the Christians as still a majority in the towns of Qabala and Šabaran (near Quba). In the Byzantino-Sasanian wars, the Albanian kings sometimes had to supply contingents for the imperial Iranian army, and Urnayr participated with Shapur II in the siege of Amed in 359, but more generally they combined with their fellow-Christian Armenian princes in resisting Persian expansion into Transcaucasia and Armenia, at times even paying tribute to the Byzantines.
The "Albanians" Buniatov was referring to have nothing with the nation in the Balkans. This was the name the Romans gave to a Caucasus people when they first made incursions into the Caucasus in the first century B.C. When Buniatov began to popularize the subject in the 1960s, the Caucasian Albanians were a long-forgotten ancient people. The scholar consensus was that they were a Christian people or group of peoples who had mainly inhabited what is now the north of Azerbaijan.
Caucasian Albanians were one of the Ibero-Caucasian peoples, the ancient and indigenous population of modern southern Dagestan and Azerbaijan.
No text in Caucasian Albanian has survived, hence any attempt to link ancient Albania with modern Azerbaijan must remain pure speculation, though these speculations payed an important part in the Azerbaijani nation building process from the 1960s onward. 
At the beginning of the first [section of this] history we placed [accounts of] the holy Illuminator of the Armenians, the apostle, martyr, and coadjutor of the three blessed  Apostles Thaddeus, Bartholemew, and James-Judas, that is, blessed Gregory, and through his prayers we have reached this far. Now for the second section [we begin with] a chapter on the illuminators of the Aghbanian areas, since they are our relatives and coreligionists, and especially since many of their leaders were Armenian-speaking, their kings obedient to the kings of the Armenians and under their control, their bishops ordained by Saint Gregory and his successors, and their people remained with us in orthodoxy. For these reasons it is fitting to recall the two peoples together. Therefore we will begin by concisely describing their leaders up to the point where we left off.
They say that the initial cause of the illumination of the eastern areas was the blessed Eghishe (pupil of the great Thaddeus the Apostle) who, after the death of the holy Apostle went to Jerusalem to James, the brother of the Lord, received [g192] ordination as bishop from him, and then went to the land of Iran eventually reaching the land of the Aghbanians. He came to a place called Gis and built a church there, and he himself was martyred there, though it is not known by whom. His body was thrown into a well with other corpses and it remained there until the time of pious King Vach'agan the last.
 Here are the kings of the Aghbanians from the line of Hayk, descendants of Arhan whom the Parthian Vagharshak set up as overseer and prince of those areas. First Vach'agan, Vach'e, Urhnayr. The latter came to the great king of the Armenians, Trdat, and to Saint Gregory and was baptized by him; and Saint Gregory gave to King Urhnayr a man from among his deacons who had come with him from Rome, and whom [Gregory] had ordained as bishop. Vach'agan, Marhawan, Sato, Asa, Esvaghen. In the days of the latter king, the venerable Mesrop made alphabets for the Armenians, Georgians, and Aghbanians. [Then] Vach'e [ruled]. Yazdigert, king of Iran, who destroyed the holy Vardaneans forcibly made [Vach'e] a mage, but subsequently he left magianism and his kingdom with it, became an ascetic adhering to a severe discipline, and reconciled himself with God against Whom he had sinned. Then the pious Vach'agan ruled, whom we recalled above. He heard that they had thrown blessed Eghishe['s body] into a well and he ordered that all the bones found [in the well] be removed. They removed them and piled them into heaps. The pious king prayed to God that the bones of Saint Eghishe be [g193] revealed. A fierce wind arose and scattered across the face of the plain all the bones except for those of Saint Eghishe. Thanking God, the king gathered them up and distributed [the relics] throughout his realm.
 Then holy Shup'haghishoy became bishop. However we are confused about his placement, for the man who wrote the history of the Aghbanians [translator's note: See the History of the Caucasian Albanians by Movses Dasxuranci, C.J.F. Dowsett trans. (London 1961)] places his name in the time of the pious Vach'agan, proof of which being the canons which Vach'agan established with all the bishops of the Aghbanians, writing: "I Vach'agan, king of the Aghbanians, and Shup'haghishoy, archbishop of Partaw." Elsewhere this name is not found again among the ranks of the bishops. But as we have found it, so we have written it.
Then lord Matt'e, lord Sahak five [years], lord Movses six [years], lord Pant seven [years] lord Ghazar eight [years]. Then the blessed youth Grigoris, son of great Vrt'anes brother of Yusik, grandson of Saint Gregory whom the great king of the Armenians Trdat sent and who was killed on the plain of Vatean as a martyr of God, [was patriarch]. His body was brought and buried at Amaras. Later, during the time of Vach'agan, relics were discovered among which were those of the blessed Zak'aria, father of John the Baptist and of Pantaleimon the great martyr for Christ who was slain in the city of Nicomidea in the time of Maximianos [and whose relics] Saint Gregory had taken with him.
 Then lord Zak'aria [ruled], ten years, [followed by] lord Dawit' for eleven years, and lord Yovhannes (who also was bishop of the Huns), twelve years, lord Eremia, thirteen years. In Eremia's time the venerable Mesrop created the Aghbanian alphabet with great effort. Lord Abas [ruled] for fourteen years. The Council of Dwin wrote to Abas that he should recite the formula "Holy God, immortal, Who Was crucified" and "of one nature, divine and human." Lord Viroy for thirty-three years. He was a prisoner for many years at the court of Xosrov, the Iranian king, but after Xosrov's death he was freed and came to his own country. He freed the Armenian, Georgian and Aghbanian prisoners from the Xazar Shat' (son of Jebu Xak'an who had enslaved the land). He built six cities named after Shat': Shat'arh, Shamk'or, Shak'i, Shirvan, Shamaxi, and Shaporan. Lord Zak'aria [who ruled for] fifteen years, saved the great city of Partaw from slavery by his prayers. Lord Yovhan [ruled for] twenty-five years. Lord Uxtanes, twelve years. [g195] [It was Uxtanes] who cursed the Aghbanian naxarars for their foul mixed marriages, and all of them died. Then lord Eghiazar [ruled for] six years. Lord Nerses [ruled for] seventeen years. While [Nerses] was bishop of Gardman, he convinced a certain woman named Spram, the wife of an Aghbanian prince, that if she had him ordained kat'oghikos of the Aghbanians, he would do whatever she wanted. The woman was steeped in the Chalcedonian heresy.  She entreated the bishops to ordain Nerses Bakur as kat'oghikos of the Aghbanians.
After some time had passed, the heresy which she had conceived within her became apparent. As soon as she was reprimanded by the bishops and priests, she began persecuting many of them. The spiritual leaders of the Aghbanians assembled and anathematized her and wrote to the kat'oghikos of the Armenians, Eghia, to aid them.
Eghia wrote [a message] to the head of the Tachiks, Abdlmelik', to the effect that "The [religious] leader of the Aghbanians and a woman here want to place their land in rebellion against you, for they are assisting the Greeks." Abdlmelik' commanded Eghia to go to Aghbania and dethrone him and to send him and the woman to court with their feet bound and thrown onto camels like freight, so that they would be the objects of derision for all the troops.
Eghia and the king's eunuch went to the city of Partaw and executed the royal order. While they mocked him thus with dishonor, Nerses died bitterly from exasperation, eight days later. [g196] All the Aghbanians naxarars and all the bishops gave  pledges before the eunuch with the royal command and seal that they would not ordain an Aghbanian kat'oghikos without the order of the Armenian kat'oghikos.
Then Eghia ordained for the Aghbanian [patriarchal] throne lord Simeon, who removed the disturbance caused by Nerses. [Simeon] reigned for one and a half years and established canons with seven provisions.
Lord Mik'ayel [reigned for] thirty-five years. He summoned the prior of Mak'enots'ats' [monastery], Soghomon, and cursed those who had married their relatives in the third degree. These were generally eliminated. They also anathematized the Georgian [spiritual] leader T'alile, for he had authorized the illegal marriages. Then lord Anania [ruled for] four years. Lord Yovsep' [ruled for] seventeen years. In the fifth year of his reign the two hundredth year of the Armenian Era was completed [751/52]. Lord Dawit' [ruled for] four years. [Dawit'] freed Church lands and ornaments. He died of poisioning. [Another] lord Dawit' [then ruled for] nine years. He sold Dastakert and Sahmanaxach' to the infidels. Lord Matt'eos [ruled for] one and a half years; he too was given poison to drink and died from it. Lord Movses, one and a half years; lord [g197] Aharon two years; lord Soghomon, half a year [Editor K. Melik'-Ohanjanyan has inserted this patriarch from the list Kirakos was using, i.e., the list in Book III of Movses Dasxurants'i's History of the Caucasian Aghbanians]; lord T'eodoros  four years; lord Soghomon, eleven years; lord Yovhannes, twenty-five years. [Yovhannes] moved the kat'oghikosate to Bardak which was their summer residence when it was removed from Partaw. Lord Movses [ruled for] one half year; lord Dawit', for twenty-eight years. It was [Dawit'] who blessed the impious marrage of the lord of Shak'i. Now the prince's lay brother asked [Dawit']: "Whence do you come, lord?" And [Dawit'] replied: "From your brother's house." Then the prince said to Dawit': "May your tongue, which blessed this not speak, and may your eye dry up." And this very thing happened immediately, nor was [Dawit'] cured until his death.