[3] Due to the historic significance of Zoroastrianism in the region, many believed that Zoroaster was Azari, although modern scholars have not reached an agreement on the location of his birth.
[6][7] Mannea was a kingdom in Iranian Azerbaijan which ruled a region south-east of Lake Urmia centered around modern Saqqez.
The Seleucids of Persia declined in 247 BC, afterwards the Kingdom of Armenian captured parts of Caucasian Albania.
[16]: 71 Between the ninth and tenth centuries, the Arabs began to refer to the region between the Kura and Aras rivers as Arran.
[17]: 48 Azaris resisted Islam for centuries and their resentment grew as Arabs began migrating to cities such as Tabriz and Maraghah.
According to Vladimir Minorsky, the sedentary population of Azerbaijan were mostly peasants at the time of the Muslim conquest of Persia and were known as "Uluj" ("non-Arab").
[21] Oghuz Turks migrated to Azerbaijan in large numbers, and it remained high through the Mongol period, as the bulk of the Ilkhanate troops were Turkic.
Turkic elements in Iran were predominantly Oghuz, with lesser admixtures of Uyghur, Qipchaq, Qarluq as well as Turkified Mongols.
[25] Russian scholar Rostislav Rybakov claimed that Iranian Azerbaijan was almost fully Turkified by the 14th and 15th centuries.
[19] Professor Xavier De Planhol also added that Azerbaijani descended from Iranian peasants who began speaking Turkish.
[27] Tadeusz Swietochowski stated that "Azerbaijan maintained its national character after its conquest by the Arabs in the mid-seventh century A.D. and its subsequent conversion to Islam.
The process of Turkification was long and complex, sustained by successive waves of incoming nomads from Central Asia".
[41] Mohammad Khiabani also preferred the Iranian identity of Azerbaijanis and supported the Persianization of Azerbaijan.