Chantepie's Lehrbuch was highly influential, and many researchers began similar efforts after its publication and its subsequent translation into English and French.
In defining the religious essence of which he explores historical manifestations, Kristensen appropriates Rudolf Otto’s conception of das Heilige ("the holy" or "the sacred").
Consequently, he reduced his field of research to the phenomena in religions living around the origin of Christianity: during the millennia before and the centuries after Christ, in Iran (Avesta), Babylonia and Assyria, Israel, Egypt, Greece and Rome.
The required knowledge of speeches, also, is one of the causes that only few (Van der Leeuw, Bleeker) of his pupils did carry on in his line, although many scholars showed interests in the results of his research.
[14] Van der Leeuw correlates subjective experience, expression, and understanding with three objective levels of appearing—relative concealment (Verborgenheit), relative transparency (Durchsichtigkeit), and gradually becoming manifest or revealed (Offenbarwerden), wherein the understanding of what is becoming revealed is the primordial level of appearing from which the experienced concealment and expressed transparency of appearing are derived.
[15] Because van der Leeuw, like Kristensen, appropriates Otto's concept of das Heilige in defining the essential category of religion, the transcendence becoming revealed in all human understanding can be further described as sacred — an overpowering “wholly other,” which becomes revealed in astonishing moments of dreadful awe (Scheu) and wonderful fascination.
[17] Moreover, van der Leeuw recognizes that, although dreadful, Being-in-the-world is fundamentally characterized as care (Sorge), the existential structure whereby Dasein is concerned with meaningful relationships in the world alongside other beings.
Among other great phenomenologists who worked and influenced phenomenology of religion are Henry Corbin, Ninian Smart, Mircea Eliade, and C. Jouco Bleeker.