In first half of 5th century AH, the most brilliant period of Islamic Architecture began in Iran. In this dynasty, we
can see the culmination of an architectural style (sabk) called "Razi Note 26". Pope relates the advent of geometrical
school to after this century in Grand Iran. Moreover, he, undoubtedly, considers geometrical decoration in Iran as
a result of direct employment of mathematical systems (Pope, 1971).