In the history of Azerbaijan, the Early Middle Ages lasted from the 3rd to the 11th century. This period in the territories of today's Azerbaijan Republic began with the incorporation of these territories into the Sasanian Persian Empire in the 3rd century AD. Feudalism took shape in Azerbaijan in the Early Middle Ages. The territories of Caucasian Albania became an arena of wars between the Byzantine Empire and the Sassanid Empire. After the Sassanid Empire was felled by the Arab Caliphate, Albania also weakened and was overthrown in 705 AD by the Abbasid Caliphate under the name of Arran. As the control of the Arab Caliphate over the Caucasus region weakened, independent states began to emerge in the territory of Azerbaijan.

In 252-253 AD, Caucasian Albania was conquered and annexed by the Sassanid Empire. It became a vassal state, but retained its monarchy; however the Albanian king had no real power and most civil, religious, and military authority lay with the Sassanid marzban (military governor). After the Sassanids’ victory over the Romans in 260 AD, this victory, and the annexation of Albania, were described in the trilingual inscription of Shapur I at the Ka’be-ye Zartošt at Naqš-e Rostam.

A relative of the Sasanian king Shapur II (309-379), Urnayr came to power in Albania (343-371), and pursued a partially independent foreign policy. Urnayr allied with Shapur II, and according to Ammianus Marcellinus, provided military forces (especially cavalry) to Shapur II's armies in their attacks against the Romans, especially in the siege of Amida (359). This ended in the victory of the Sassanid army and as a result, Artsakh, Marlar (now Nakhichevan), Caspiana and other regions of Albania were returned. He also noted that Albanian cavalry played a determinative role in the siege of Amida, like the Chionites (Xionites). After this victory, Shapur II began to oppress the Christians in Albania.

“Close by him [Šapur II] on the left went Grumbates, king of the Chionitae, a man of moderate strength, it is true, and with shrivelled limbs, but of a certain greatness of mind and distinguished by the glory of many victories. On the right was the king of the Albani, of equal rank, high in honour”.

In 371, the battle of Dzirav (also known as the battle of Bagavan) took place between the Romans and Sassanid armies. Albania was the Sassanids' ally in this battle too. The battle resulted in the victory of the Roman army. Urnayr was wounded and Albania was deprived of provinces like Uti, Shakashena (Sakasene), Colt (Albania's western border province) and the Girdiman valley [az] in this battle. Albania regained its lost provinces with the treaty signed between Rome and Sasanids in 387. In 450, the Sasanian army was defeated by Christian insurgents against the Persian Zoroastrianism of King Yazdegerd II in a battle near the city of Khalkhal (present Gazakh region) and Albania was freed of Persian garrisons. After the death of Yazdegerd II, an intense fight began for the throne in Iran between Yazdegerd's sons Hormuzd and Peroz. The return to Christianity of Vache II resulted in a war between Persia and Caucasian Albania and Vache II declared his recalcitrancy to the new Sasanian ShahenShah Peroz I. After this distrust, Peroz raised the Haylandur [tr] (Onoqur) Huns to fight the Albanian monarch. They occupied Albania in 462. This fight ended with the abdication of Vache II in 463. Albanian historian Moisey Kalankatlı [az], wrote that Albania then remained without a ruler for 30 years. The northern part of Azerbaijan became a marzbanianity of the Sasanian Empire.

According to Kalankatli, almost 30 years later, the monarchy of local rulers was reestablished in Albania by the nephew of Vache -- Vachagan III (487-510). Vachagan Barepaš (the pious) was enthroned by the Sassanid shah Balash (Valarsh) (484-488). Vachagan III restored the concessions of the Albanian tsars, reduced taxes, and granted freedoms to Christians.

Independent state institutions were eliminated in the South Caucasus by Sassanids in 510. Sassanid governors-general began a long period (510-629) of domination in Albania. In the late 6th to early 7th centuries, the territory of Albania became an arena of wars between Sassanid Persia, Byzantium, and the Khazar Khanate, the latter two very often acting as allies against Sassanid Persia. In 628, during the Third Perso-Turkic War, the Khazars invaded Albania, and their leader Ziebel declared himself Lord of Albania, levying a tax on merchants and on the fishermen of the Kura and Araxes rivers "in accordance with the land survey of the kingdom of Persia".

The reign of the Mihranids dynasty (630-705) arrived in Albania in the early 7th century. This dynasty originated from Girdiman province (now the Shamkir-Gazakh region of Azerbaijan) of Albania. Partav (now Barda) was the centre of this dynasty. According to Kalankatli, the initiator of the Mehranids’ dynasty was Mehran (570-590), and the representative was Varaz Grigor (628-642), who took the title “Prince of Albania”.