Realist ontologies claim to represent what exists. However, human behaviour and culture is deeply influenced by religious and spiritual belief, whose veracity is highly controversial. Such beliefs are nevertheless known to have substantial impact on well-being, social behaviour, health and disease. It is therefore desirable to be able to represent beliefs within a principled ontology using the Web Ontology Language (OWL) as a standardised representation language. This paper demonstrates how a realist ontology, expressed in description logics, can deal with such entities without requiring consensus about their existence in reality. We present several ontology design patterns which allow for taxonomically arranging elements of religious or spiritual belief systems. This provides a framework on which data on particular beliefs can be better standardised for research in humanities, social research and life sciences.