The framework within which events unfold is made up of two Christian religions: Protestantism and Catholicism. In Scotland, both religions were viewed as polar opposites. Miss Brodie was brought up under the Church of Scotland, meaning that she was a Protestant, and she also followed Calvinist teachings. Calvinism, in Protestant Christianity is the theology developed and advanced by John Calvin. It forms the foundations for Presbyterianism and is vased on the beliefs that:
             1. there is a hell to which some human beings will go;
             2. most human beings will end up in hell;
             4. God planned who will and who wont go to hell;
             5. everything which happens is God's will;
             6. the individual makes no independent choices and has no free will;
             7. we cant be given credit/condemnation for the good and bad things we do as everything is God's will;
             Sandy becomes a Roman Catholic (which is the religion Muriel Spark was converted to in 1953). The process of conversion is not described in the novel, but Sandy's interest in this religion seems to have been triggered off by her adulterous affair with Teddy Lloyd:
             By the end of the year it happened that she had quite lost interest in the man (Teddy) himself, but was deeply absorbed in his mind, from which she extracted, among other things, his religion as a pith from a husk. Her mind was as full of his religion as a nig ht sky is full of things visible and invisible. She left the man and took his religion and became a nun in the course of time.
             What is interesting is that, despite Spark's own conversion to Catholicism, it is unclear whether Catholicism is shown in a favourable light. On no account does Sandy, now Sister Helena of the Transfiguration, give us the impression that her soul is at peace:
             She clutched the bars of the grille as if she wanted to escape from the dim parlour beyond, for she was not
             ...