According to Pope Benedict XVI, the Catholic building church after the Second Vatican Council reduced the value of sacredness so that the sacredness of the expression of the form of a Catholic church is considered to fade. This statement from the Pope is exciting to be an issue for researchers to search for indicator values of the Catholic Church’s sacredness before the Second Vatican Council. The Cathedral Church was founded before the Second Vatican Council. This study’s method is a quantitative method by taking as many as 250 respondents who were grouped as users and observers as defining the population and purposive sampling to determine the impression of the sacredness felt by respondents through several indicator values. The conclusions obtained in this quantitative analysis are the sacred indicator values of the church received from; (1) Variables of the liturgy function; (2) Variables of form expression. The findings in this study are: (1) The Catholic Church founded before the Second Vatican Council is still imperfect; that is, this church is not following its ritual function. (2) The expression of the Catholic Church’s form can be said to be sacred if the form’s concept follows the function by considering indicator values of sacredness.

In the Postmodern era there are diverse forms of architecture, which is also related to. structural and material technology that is developing so rapidly. The method used is the analysis of architectural theories to find the relationship between Function‐Form, whether: 1) The concept of Form follows Function; 2) The concept of Function follows Form; 3) The concept of Form and Function runs together. The relation between the concept of Function and Form will result in the meaning of the architectural work itself. The conclusion is: in architectural design there is no exact rule whether the Function must follow the Form, or Form must follow the Function, or Function and Form run side by side, but the relationships between Function and Form merge into a single method towards the expression of architectural Form, so that this Function‐Form relationship will be interpreted by the observer towards the expression of the architectural creation itself. The findings in this study are to give architectural designers freedom regarding the relationship between Function‐Form. However, the most important thing from this relationship is that the meaning must be reflected in the expression of the form that corresponds to the relationship to be achieved. The benefit of this research is that architectural students can know more deeply the relationship between the Function‐Form that will be used in the design, and also for architect practitioners in designing the building.