Islamic historical schools are a manifestation of the distinguished culture and advanced civilization of Islam; however, despite researchers’ attention to the study of various cultural aspects of Islam, this valuable area has not been sufficiently analyzed. In Iranian school architecture, the spectrum of form and function serves as a domain for classifying the features of open and semi-open spaces, revealing their similarities and differences. This spectrum has not yet been used for a comparative study to classify the characteristics of open and semi-open spaces in Iranian school architecture. This research aims to answer two questions: What is the arrangement pattern of open and semi-open spaces in historical schools of the desert and central regions of Iran, and which factors have had the greatest impact in creating differences and similarities in the formal design of schools in these regions? In this regard, nine samples were purposefully selected from among the existing historical schools in these regions. The following criteria were considered in selecting samples from all historical schools in Iran: location in a similar climate (desert and central regions of Iran), typological distinction as schools rather than mosque-school complexes, representation across different historical periods (Ilkhanid to Qajar), and selection of schools whose open and semi-open spaces exhibit changes in form and function compared to other schools. Using a comparative analytical-descriptive research method, common patterns in the design of open and semi-open spaces were identified. Data for this research were collected through fieldwork, library studies, and cultural heritage documents. The results showed that in some cities, such as Yazd and Kashan, the patterns are more similar due to the use of garden courtyards (ḥawż-bāgh). Additionally, the issue of function and the addition of new uses to schools and open spaces appeared in various forms. Ultimately, functional considerations contributed the most to creating differences, while climate and geometry—particularly in the domain of proportions (Iranian golden ratios)—were influential in creating similarities.
