Evolutionary Trend of the Title " Zill-ullah" Throughout the Medieval Period of Iran History According to Historical sources and Andarz Nameh

Abstract:This research seeks to review evolutionary trend of the title “Zill-ullah” (the shadow of God) applying for the Iranian kings (Sultans) in medieval period as well as to describe its usage as cited in historical sources and mirrors for princes (Andarz Nameh). Therefore¡ this research endeavors to answer these questions: What was the historical trend of using Zill- ullah in historical sources and the mirrors for princes and since when and why it had been used and applied as the title of kings? The findings which is based on historical explanation¡ demonstrates that Zill- ullah had basically used in historical sources to describe the Caliphs. Since the 5th century (AH) onward¡ it had limitedly been used only to tribute some sultans but not as a title. In early medieval it used to refer to a legitimate just king but gradually it was routinized so then referred to the governors¡ either being righteous or oppressor. This research also proves that the trend of transferring this title from the Caliphs to Sultans at first had started in historical sources and then in mirrors for princes. However¡ after Ghazali’s Nasihat al muluk¡ some of the mirrors for princes also played an important role to support the Sultanate concept of Zill-ullahi through using various justifications.