An exploratory study on the design schemes underlying two architectural precedents is presented and discussed.The study compares the formalistic compositions of two prominent precedents on multiple levels.These levels include the morphological,semantic,and pragmatic layers.The morphological aspects of these layers are emphasized.The study aims to identify the commonalities and differences between two cases of classical sacred architecture in terms of their morphometric and morphosyntactic structures.These cases are represented by Paltadio’s Ⅱ Redentore Church and Sinan’s Süleymaniye Mosque designs.The scope of the analysis focuses on the syntax and mathematics of the floor plans,and the facade and section of each case are referenced occasionally.Within this scope,the proportional system that regulates the compositions and eidonomy of the precedents are scrutinized.Findings resulting from the comparative analysis are reported and then discussed.The study shows that the two ostensibly different precedents share obscurely many commonalities,which are greater than what their initial appearances suggest.