Comparative study of the plastering designs of Sassanid and Seljuk eras in Khorasan‎(Case study: Historical Monuments of Dargaz and Robat Sharaf)‎

One of the most significant Iranian architectural elements employed in the interior decoration of structures during the Great Khorasan era, before Islam, and the Islamic era is plaster design, which is renowned for its wide range of designs and superior craftsmanship. The closest comparable examples may be found in the Seljuk period. It appears that the plaster decorations of the Islamic period of Khorasan were produced based on the history of pre-Islamic plaster art. The two historical monuments of Robat Sharaf from the Seljuk era and Dargaz from the Sassanid era, which are the nearest landmarks of Khorasan in terms of time in both the pre-Islamic and Islamic periods, are the subject of this study. Plastering is one of its significant arrays. The majority of Sassand-era plastering structures can be found at the Dargaz Archaeological Site in northern Khorasan, which also displays the magnificence and splendor of that period's plastering culture. Additionally, Robat Sharaf holds a unique place in the history of Khorasan architecture during the Islamic era. This building is renowned throughout the world for its stunning gypsum arrays and their combination with brickwork, which is reminiscent of the continued practice of plastering from earlier times. The need for such research is highlighted by the paucity of research on the impact of Sassanid bedding art and the use of its motifs on buildings from the Islamic era in Khorasan. Consequently, the following inquiries are made in light of the significance of this matter in the development of Khorasan's art and architecture: what features, focusing on two renowned historical sites, distinguish the plaster patterns of the Sassanid and Seljuk eras in Khorasan? What similarities and distinctions exist between them? The analytical-comparison method was used in this study, and the findings demonstrate the stability of this art form after more than five centuries by demonstrating how many of the interior plaster decorations of the Robat Sharaf building, particularly in plant and geometric designs, are similar to Dargaz building.