From the 7th to the 10th century Azerbaijan was subject to the Arab Caliphate, under whose rule the country was Islamized (except for some Caucasian Albanians, especially in Qarabağ, who remained Christians). Despite a certain economic upturn and numerous prosperous cities, the Azerbaijanis perceived the Arab rule as subjugation. It is certainly no coincidence that one of the strongest rebellions in the Arab Caliphate took place under the direction of Babek in Azerbaijan, who from 818 until 838 fought against the foreign exploiters, defeating six of the Caliphate’s armies.
The 9th century saw the formation of autonomous feudal states on Azerbaijani lands. The most stable among them was the state of Shirvanshahs, which survived until 1538. Azerbaijan became a part of the Seljuk Empire in the 11th century.
Under the Seljuk rule, the immigration of Oghuz Turkic tribes further strengthened the ancient and already dominant Turkic presence in Azerbaijan. The 12th century marked the emergence of the powerful state of Atabeys (Eldegizes) and the “age of the Muslim Renaissance’’ in Azerbaijan. This “renaissance” owed its glory, among others, to the literary genius of poets like Nizami Ganjavi, Mahsati Ganjavi, Abu-l Ula Ganjavi, Falaki Shirvani, Khaqani Shirvani, and the architect Ajami Nakhchivani. Azerbaijani literary and architectural masterpieces became an outstanding contribution to the world’s cultural heritage.
The 13th century marked the renaissance of Azerbaijani science. Nasiraddin Tusi was the most renowned Azerbaijani scholar of this century. In 1259, he established the observatory at Marağa, which became the most important mathematical-astronomical school of the Islamic Middle Ages. Tusi is regarded as the first mathematician to separate trigonometry from astronomy. He authored noteworthy works on arithmetic and algebra. His works, which remained valuable for centuries past his own times, have been translated into Latin and published in Europe.
The Caucasian Albanian Principality of Khachen in the region of Nagorno-Karabakh (Mountainous Karabakh) had its heyday in the 12th and 13th centuries. The rule of Hasan-Jalal (1215-1261) led to an Albanian Renaissance and the construction of the Ganjasar Monastery was completed under him.
The invasion of the Mongols in the 13th century was a serious setback, but Azerbaijan recovered from this immediately afterward. At the beginning of the 14th century a new ascendancy by the Shirvanshahs began in the north, while Garagoyunlus and later Aghgoyunlus emerged in the south.
Founded in 1501 the Safavid state with its capital Təbriz unified all the regions of Azerbaijan for the first time. The founder of this state was Shah Ismail I (reign 1501-1524), also known as the famous Azerbaijani poet under the nom de plume Khatai. The Safavid Kingdom stretched from the Amu Darya River in Central Asia to the Euphrates in Iraq and from Dərbənd in the North Caucasus to the coast of the Persian Gulf and included a total area of 2,800,000 square kilometers.
It was at this time that Azerbaijani was established as the state language, and the sciences, particularly the natural sciences, flourished.