The evolution and changing in the course calendar and study symbols of ancient Iranian calendar in the Islamic Numerical calendar

Persian calendars besides having the most unique art forms have strong academic Foundations, too. These images (Art forms) are re¬flected in the domain of Persian art. In the present article has been tried to study the process of changes and evolutions of calendars. This research also tries to explain the oldest samples of Persian chronology. In addition, by study the samples of Islamic Numerical calendars (Roghomi calendars), has been tried to show the elements of ancient Persian chronology that have been used in these calendars. The aim of this study is explaining continued life of symbols and sings related to ancient chronology in this Numerical calendars. This study proves the hypothesis that there has been chronology since from ancient time and in different periods in this country. The symbols and sings of ancient solar calendar have appeared in Islamic period at Numerical calendars in both written and pictorial forms. The adopted method in this research is descrip¬tive – analytic via library researches and with taking notes method. Also samples of calendars that exist in libraries and museums have been studied through of fieldwork. In this reason, at the first, chronology of pre Islamic and Islamic periods has studied, and the types of chronology in these times have explained. It explains constellation as relative symbols with Persian chronology and shows samples of it, in ancient Persian art. Then, by offering a report of some Islamic calendars; it talks about the processes of changes and evolutions of these calendars and the contact of ancient calendars with some samples of contemporary calendars. Then it indicates the symbols of ancient Persian chronology (like constellation) in the contemporary calendars. According to the results of this research, icons of calendar have been appeared on Persian artworks very well, from pre-Eilamit history to Sassanid period. These forms (icons of calendar) are seen on the artworks, calendar and astronomical texts in Islamic periods. In this period the name of these constellations is existed in calendars in the form of written and image. Numerical calendars (Roghomi calendars) have the same structures with ancient astronomical tables (horoscopes), that were known from the Achaemenid era. From that time (Achaemenid period) should not be ignored effects of horoscope, the element that in special form are in Islamic calendar. The oldest Persian chronology which is solar with content and visual features, has survived in Islamic period; these features are observed in Numerical calendars.