Two basic pillars have caused the change of the older Iranian music system to instrumental music: first, the internal factor that has an inherent origin, and second, the external factors.  We will look for the internal factor here in the emergence of the “leader’s tone” and the use of the variety of “tunes” and the external factor in the role of culture.

The artistic phenomenon of device in Iranian music is a complex and historical phenomenon.  The fate of the history of its origin should be sought in the history of culture, especially from the Mongol era onwards.  The main reason is that in the theoretical works before this era, there is no sign that can reveal much news about its existence to us.  Culture creates a phenomenon and is sensitive to its importance and place, and tries to protect and grow it;  It is for this reason that we say that the phenomenon of the device has developed parallel to and within the cultural history of this land.  What is clear in the history of the origin of the device is that this phenomenon started growing from a nascent state at the same time as the Mongol era, in the geography of western Iran, and has continued to grow until today.  The initial picture of its emergence is that one mode (Mode) attracted other modes to the state of polarization (polarization) through the turning of the curtain and this state gradually expanded (Old Schools 2013 p. 211-  381 \ An introduction to ethnic musicology 2006 pp. 461-509).  The origin of the word device is related to the issue of its apparent naming whenever it wants to return, which does not inform us about the history of its internal content and the causes of its appearance (1).

Although I have written about this topic in detail in the chapter “East and West of Iran, Two Different Cultures in Perdganism and Instrumentation” in the book An Introduction to Ethnic Musicology (1386), I will mention a few points here.  We said that instrumental music is a product of western Iran.  If a hypothetical line is drawn from Tehran to the south, this line divides Iran into two parts, east and west.  This division is presented by the Russian historian Barthold from the historical aspect, Mehrdad Bahar from the mythological aspect and Andre Godar from the architectural point of view, and others such as Basvert, Zazeh, Herzfeld, Hartman and Strygosky discuss about the history of culture.  East and West of Iran have also paid (Hajarian 1386 p. 467).  The western region of Iran has seen Shiism and Ghazal lyricism and all the thrones of Iranian sultans after the Mongols.  What is the subject of our discussion here is that instrumental music has many coordinates, the main of which is the combination of “modes” with the priority role of “income” and the hierarchy of modes.  Safi al-Din Ermoy himself refers to the combination of fashions, but almost the first source that explicitly mentions this point is Qutb al-Din Shirazi in his book Dara Al-Taj (2007, pp. 148 and 149), followed by Abdul Qadir Maraghi and after that.  Others have mentioned the combination of modes.  Since then, many treatises have mentioned the combination of fashions, the most extensive of which is the famous Musa’s row in the contemporary era.