The article below by Professor J. During on the history of music in Azarbaijan was originally posted in the Encyclopedia Iranica.
The art music of Azerbaijan is connected with the Irano-Arabo-Turkish art of the maqām, of which the great theoreticians were notably Ṣafī-al-dīn Ormavī (d. 693/1294) and ʿAbd-al-Qāder b. Ḡaybī Marāḡī (d. 838/1435), who were originally from Urmia and Marāḡa in Azerbaijan. According to Hajibekov, this tradition collapsed at the end of the fourteenth century (with the Mongol rule), and subsequently each national group reconstructed its own system from the debris (1945, p. 18). The names were preserved, but the realities to which they applied varied from one tradition to another. In the same way the old rhythmic patterns (oṣūl) disappeared in favor of several simple formulas, mainly in 6/8 and 4/4. It seems, however, more correct to locate the break in the traditional chain of transmission in the 12th/18th century. This period was followed, at the beginning of the 13th/19th century, by a revival, in the course of which the remains of the old system were enriched by popular contributions. In the course of this evolution the art music of Azerbaijan remained intimately linked with that of Iran, to which it is still very close. In the absence of documents, this process of revival still remains quite obscure, but it may be located in the southwest and northwest of Iran. In the northwest, it was particularly the town of Šūša in the Qarabāḡ mountains that was the focus of musical life, but it was at Tiflis that Caucasian musicians found the widest audience. Since the beginning of the century the most active musical center has been Baku.
The Iranian elements in the development of the Azeri tradition were numerous, as is shown by modern terminology (čahār meżrāb, bardāšt), as well as by certain pieces in the repertoire, recent gūša and maqām that have Iranian names (Bayāt-e Šīrāz, Šūštar, Delkaš, Šekasta-ye Fārs, Bayāt-e Qājār). Conversely, Azerbaijani elements are found in Iranian music, particularly in dance pieces (reng). (See also M. Rezvani, Le théâtre et la danse en Iran, Paris, 1962, p. 149.) Azeri art music is also played in other regions of the Caucasus, especially among the Armenians, who have adopted the system of maqām and the instruments kamāṇča and tār. Aside from these recent and older Iranian elements (the majority of the names of the maqām are already found in such Safavid sources as Behjat al-rūḥ, attributed to ʿAbd-al-Moʾmen b. Ṣafī-al-dīn), a certain number of maqām and melodic patterns are typically Azeri or have gradually become so (e.g. Segāh, Čārgāh, Welāyetī, Qaṭār, Mobarqaʿ, and Kord-Šahnāz).
The musical traditions of Azerbaijan were already distinct from those of the area now known as Soviet Azerbaijan, but they became definitively separated toward the end of the 13th/19th century, with Iranian Azerbaijan opting for the purely Iranian style. Subsequently the music of the Soviet Azerbaijan underwent a period of Western acculturation marked by the reduction of the seventeen intervals in the octave to twelve tempered half tones, the integration of Western instruments, polyphony, and orchestration. On the other hand, a music that is Western in form but national in style developed, integrating such traditional elements as instruments (tār, kamāṇča, daf, and bālamān), rhythms, modes, and melodies. The founder of this new school was Hajibekov (1895-1948).
Ultimately acculturation has not deeply affected the old music, which is still performed by great interpreters faithful to their tradition. In the popular domain, the ʿāšeq (q.v.) bards have never stopped singing in cafes and at family celebrations, accompanying themselves on the sāz (čoḡūr in Azerbaijani Persian) and also accompanied by the reed flute (bālamān) and the tambourine (qawan