پژوهشی بر کاربرد یک فرم تزیینی در کتیبه نگاری محراب های گچ بری دوران سلجوقی و ایلخانی در ایران

Introduction: Inscriptions are considered as one of the most significant form of decorations that have been used mostly in the mihrabs and involve Quranic verses, prophet’s sayings, religious expressions as well as the date and the name of their creators. The stuccoed mihrabs of the Seljuk and Ilkhanid periods were no exception in which the inscriptions have many visual features including using a letter/ word or a decorative form at 45° angles of the inscriptions all around the mihrabs. The aim of this research, therefore, is to identify different kinds of these letters/ words or decorative forms in the inscriptions carved around the mihrabs created during the 12th and 14th centuries and compare them with each other. Thus, the following question has been put to be answered: what are different kinds of decorative forms used in the inscriptions of the stuccoed mihrabs created during the Seljuk and Ilkhanid periods and what are their similarities and differences in terms of their functions? Methodology: This research is carried out using a historical-comparative method. Regarding the innovative theme of the article, first the attempt has been made to identify how decorative form in the inscription of the mihrab is used. Then, the researcher has tried to find this decorative form in the stuccoed mihrabs of the 12th and 14th centuries. Then, the letters/ words or the decorative forms of these mihrabs are compared and their significant features are described.   The data was collected mostly from the selected samples through field researches, i.e. photography and linear designs of the images and the provided pictures are drawn using Photoshop and Matrix. The library resources are also used to introduce the historical records and describe the stuccoed mihrabs. Conclusion:The results, obtained from studying 22 stuccoed mihrabs assigned to Seljuk and Ilkhanid periods, show that, in each period, it was common to use a word similar to لا »  «or decorative forms at 45° angles of the inscriptions around the mihrabs and they can be seen in different forms: using a single letter of the inscription (separately) that are diagonal (symmetrical) at angles; using a form like the word لا that is sometimes simple and sometimes elaborate and with detailed decorations. According to studies and the samples obtained from the above decorative form, the لا-like decorative forms can be classified into different groups that involve various types in terms of: 1) vaiation in node-like forms of the letters ل and ا and 2) the relation between the decorative form and the margin box, decoration or inscription. The node-shaped variation is such that the letters ل and ا are tied together in the middle and this tied part can be classified as triangle, square or rectangle and circle. The complexity of knitting these two letters is different and in some samples, it is so elaborate. The way these letters/ words or the decorative form are used in angles can also be considered because sometimes it is related to the margins and walls of the frame and is located such a way that its relation with the upper or lower lines of the border frame is definite and sometimes it is independently located at 45° without having to be attached to the margin box. According to the distinction of this decoration form, which varies from the sixth century to the 12th century, we can point out that at the angles of the stuccoed mihrabs of Ilkhanid period, more elaborate and detailed لا-like decorative forms were used compared with the Seljuk period and also, during the Ilkhanid period, this form has been changed to a pine fruit/ tear with various decorations this decorative form has been widely used in the inscription of the stuccoed mihrab.