In ancient Persia musicians held socially respectable positions. We know that the Elamites and the Achemenians certainly made use of musicians but we do not know what that music was like. During the Parthian era, troubadours or Gosans were highly sought after as entertainers. There are theories in Academia that perhaps the early Dari Poets of Eastern Iran like Roudaki were in fact Gosans. The history of musical performance in Sassanid Iran is however better documented than earlier periods. This is specially more evident in the context of Zoroastrian ritual By the time of Xusro Parviz the Sassanid royal court was the host of prominent musicians such as Ramtin, Bamshad, Nakisa, Azad, Sarkash, and Barbad. Among these survived names, Barbad is remembered in much documents and has been named as remarkably high skilled. He has been credited to have given an organisation of musical system consisting of seven "Royal modes" named Xosrovani, thirty derivated modes named lahn, and 360 melodies named dastan. These numbers are in accordance with Sassanid's calendar of number of days in a week, month, and year. The theories these modal system were based on are not known, however the writers of later period have left a list of these modes and melodies. These names include some of epic forms such as kin-e Iraj (lit. the Vengeance of Iraj), kin-e siavash (lit. the Vengeance of Siavash), and Taxt-e Ardashir (lit. the Throne of Ardashir) and some connected with the glories of Sassanid royal court such as Bagh-e shirin (lit the garden of Shirin), Bagh-e Shahryar (lit. the Sovereign's Garden), and haft Ganj (lit. the seven threasures). There are also some of a descriptive nature like roshan cheragh (lit. bright lights). In general the period of Xosroparvis reign is regarded as an "golden age of Iranian music" and himself is shown in a large relief at Taq-e Bostan among his musicians and himself holding bow and arrows and while standing in a boat amidst a group of harpists. The relief depicts two boats and the whole picture shows these boats at "two successive moments within the same panel". Barbad may have invented the lute and the musical tradition that was to transform into the Maqam tradition and eventually the Dastgah music. The persian music has thousands of years of history, as seen in the archeological documents of Elam, one of the earliest world cultures,which was located in southwestern Iran. There is a distinction between the science of Music, or Musicology, which, as a branch of mathematics has always been held in high regards in Persia/Iran; as opposed to Music performance, (Tarab, Navakhteh, Tasneef, Taraneh or more recently Muzik), which has had an uneasy and often acrimonious relationship with the religious authorities and, in times of religious revival, with society as a whole. Even after Islam Persian Musicians did not disappear: Zaryab is often credited with being the greatest influence over Andalusian and Spanish music. Farabi and Avicenna were not only musical theorist but adept at the lute and the Ney respectively. Traditional Hierarchies of Authenticity and Value The position of a particular work of music often depends on the music genre and its relationship to music theory. The academic Authentic Persian Music (Musiq-i-Asil) is strongly based on the theories of sonic aesthetics as expounded by the likes of Farabi and Shirazi in the early centuries of Islam. It also preserves melodic formula that are often attributed to the musicians of the Persian imperial court of Khosroe Parviz in the Sassanid Period. Dastgah is the music of those who have a greater share of, or affect to be in possession of, refined taste and high culture and as such, in spite of its present popularity, has always been the preserve of the elite. However, the influence of Dastgah can not be underestimated as it is seen as the reservoir of authenticity that other forms of musical genres derive melodic and performance ideas and inspiration. Other genres of respectable music were not as soundly based in abstract theory, but from a utilitarian point of view were useful. To this group belongs the martial music of Persia (Musiqi Razmi), whose roots go back to the Parthian era, as attested by Roman sources. This form of music has now been almost completely replaced by European forms ever since the modernization of the armed forces. This type of music with large drums, brass and reed instruments was used not only at war but also in official and solemn occasions. The Naqareh Khaneh or the house of drum, the chief exponent of this type of music survived into the Qajar Period but by this time much of the expertise, fostered during the Safavid era, had disappeared. The only trace of this form of music in a much simplified form is the music of the Zurkhaneh, the traditional martial arts of Iran, where the exercises of champions (Pahlavan, literally Parthians) is regulated by a drummer / vocalist known as the Murshid. Rock music in Iran has been influenced by many traditional forms of Iranian music and popular Western rock bands such as Pink Floyd, The Doors, Dire Straits, AC/DC, Metallica and Pantera.Iranian rock music first developed in the 1970s, but was largely silent during the 1980s, only to witness a recurrence in the 1990s. one of the notable Heavy metal bands is Angband which is believed to be the first Iranian metal act to release its work internationally through a European label